Curd! Grapefruit, lime, lemon, and orange curd are an awesome way to use up citrus. Plus, if all of this fruit came from a CSA it's probably organic, which means you can use the zest without fear.

WOW... Living in a place where you get citrus fruits in a CSA box, that must be a dream come true ;-)

What about making ice pops with some of the fruit? Just squashing the fruit, and freezing the juice in little ice pop containers? You could mix in some homemade sirup, like basil sirup or you could put in some raspberry pulp...
This way, you'll have a healthy and sweet treat whenever you feel like one.

Juice!!

Slice and dry them for use in beverages. I second the frozen juice idea and don't forget your local soup kitchen or church food pantry might really appreciate a donation.

Martha Stewart always has lots of citrus recipes that I want to try. If you have her baking book, she has recipes for all the different curds, and bars and pies and cookies.

MarthaStewart.com: Grapefruit Recipes

MarthaStewart.com: Tangerine Recipes

I have 3 citrus trees in my yard, and they fruit year-round, using all the produce is one of my greatest garden & kitchen challenges:

Lemonade and all its various citrus variations (Orangeade, Limeade, mixed is best)
Curd
Sorbet & Pops
Ice Cream
Poundcake (Ina Garten's recipe for lemon poundcake, called Lemon Cake, is good)
Angel food cake
Syrup (for cocktails & pancakes/waffles)
Candied peel
Moroccan-style salt-preserved lemons (I've done it with all citrus)
Sugar-preserved lemons (preserved in sugar syrup - you can pull them as needed to use in desserts)
Zest & juice, freeze, and you can pull as needed
Bath products (I make a lemon body scrub using the lemons from my garden)

If you want to keep them fresh far longer, immerse them completely in a bowl of water and refrigerate, change the water daily. I send boxes full to my cousin, who lives in a snowy climate, and it helps her get through the Winter. However at the first sign of the citrus skin starting to soften you have to use them and when that happens will vary (based on the weather conditions when they were harvested and the temperature they were stored at).

My first thought: send it to me!

Sorbet or Granita!!

margaritas!

I currently have a grapefruit upside down cake in the oven. Yum!

This salad is awesome: http://ohsheglows.com/2012/03/06/citrus-beet-salad-with-creamy-avocado-lime-dressing/

limoncello or any citrus variation--they will make great gifts.

If it gets colder in the evenings, or if you like 'tea', I really like this quick-to-make brew : poor boiling water over a little sugar (optional) and add a little lemon juice / throw in a big slice of lemon. You can add some honey if you like.

I even planted a few lemon seeds this year to eventually (hopefully - wrong climate here) end up with my own lemons; this 'tea' uses up a lemon pretty fast especially if you drink some each day. If you don't have lemons I'd try it with the other citrus too..

You could make sorbet, sherbet, and popsicles....

Last night I made Martha Stewart's Chicken with Tangerines and Olives for dinner. It was absolutely divine. Next time I make it, I will make a double batch so I have leftovers.

AllRecipes has the most amazing chicken recipe. Orange Rosemary Chicken. I use garden fresh squeezed orange juice (1.5 cups), fresh chives and rosemary from the garden. The recipe is amazing. Marinate the chicken and then cook. Oh my! http://allrecipes.com/recipe/orange-rosemary-chicken/detail.aspx?event8=1&prop24=SR_Title&e8=Quick%20Search&event10=1&e7=Recipe

I agree with Magzeen, especially if you have some tangerines or blood oranges.

This is a great chicken recipe with a citrus salsa that's a favorite in our family. I always double the salsa if I'm cooking for 4. <a><href="http://www.foodandwine.com/recipes/citrusy-mojito-chicken">http://www.foodandwine.com/recipes/citrusy-mojito-chicken

On of my favorite salads is simply sliced avocados and supremed grapefruit (let the juice fall into the bowl as you're cutting out the sections). It's so refreshing and simple. Sometimes, I've added mint, sometimes some feta - it's pretty flexible.

Send them to me!
...changing my username to "Jealous in Canada"

For lemons and limes I zest them and freeze the zest in freezer safe containers for use all year long. Juice goes in many ice cube trays and then I place the cubes in zip lock bags for future use. This can be used for anything from lemonade, desserts, or cooking. Grepefruits are so wonderful in morning fruit salads, and evening dinner salads. Frozen grapefruit juice makes incredible frozen marguaritas or mohitos. Hope this help!

I like to use citrus in cocktails, nonalcoholic drinks, salads, French toast, fish, and fresh juice. For more details, check out my tangerine blog post at http://foodiegoeshealthy.com/tangerine-mint-spritzer/.

Curd would be my first choice; http://sunitabhuyan.com/?p=2538 is my favorite recipe.

I have no idea what a CSA box is, but if you have lemon's you could preserve them, they're wonderful in cooking casseroles, tajines, tangias etc here is a recipe http://foodfromourlife.wordpress.com/2011/07/25/a-week-until-ramadan/ then there is Joyce's lemon cake which is a recipe I got from a wonderful French cookbook called French, it's without question the easiest cake recipe ever! But be careful as it's addictive :D
http://foodfromourlife.wordpress.com/2011/09/03/joyces-lemon-cake/

Juice them, freeze the juice for later, and candy those rinds!

I second the citrus salad suggestion, here's one I made recently. You can also use a basic key lime pie recipe and substitute any citrus to make a lemon or orange curd pie. I've done it with lemons many times!

I was also thinking juicing and freezing for future use. The ice cube tray would be a great way to do it, then transfer to a freezer bag and label. I keep meaning to do this as I often end up forgetting to buy lemons and needing just a little lemon juice for a dish.

One more thing! I've been making amazing smoothies with fresh grapefruit lately. I've been using some combination of yogurt, banana, avocado, berries, pears, etc. with grapefruit and they are delightful. The slight tang of the grapefruit balances is subtle and adds a nice twist. My 3 year old loves them too.

Orangette's Marmalade cake is an olive oil cake that uses 2-3 whole citrus fruits, rind and all. http://orangette.blogspot.com/2010/02/we-ate-this-cake.html