Ideas for Pitcher Cocktails?

There are some great suggestions here!

http://www.food52.com/foodpickle/5745-good-cocktail-to-serve-at-a-late-lunch-ideally-made-by-the-pitcher-don-t-want-to-utterly-intoxicate

(I'm still pushing for Pimms)

I'm a huge mojito fan too. Strawberry is my preference-but you can really do it up with any seasonal berry for a nice twist.

How about this: http://www.food52.com/recipes/12269_thai_one_on
I did 2 large batches (1.75 L bottle of vodka per batch) for a party, and they went over very well.

I made a cucumber/lemon spritzer with vodka - use juice from cucumbers, add lemon juice, simple syrup, mint, vodka and seltzer. You can add slices of lemon and cucumber to the pitcher for color.
Or you could always make a pitcher of Pimm's Cup. Then add slices of strawberries, cucumber and mint.

Martha Stewart has this great recipe for cherry mojitos. It is fabulous. And since cherries are in season I think it would be a great option for you. http://www.marthastewart.com/332780/cherry-mojitos

Homemade ginger syrup, soda, lemon juice, and whiskey is my favorite pitcher cocktail because it's easy, simple enough to please most everyone, and can sit for a few hours without a problem (especially if you stir it a few times). Here are the amounts I use for a single serving; I just multiply it by the number of people or how many servings I think I can fit in a pitcher: 1.5oz whiskey, .5oz lemon juice, dash (about .25oz) ginger syrup, soda water. Refrigerate it before the party so you can bring it out cold. Have your guests pour it over ice.

My husband wrote a piece on large-batch cocktails for parties here: http://drinks.seriouseats.com/2010/12/cocktail-party-tips-batching-drinks-in-advance.html

including a recipe for bottled Negronis here: http://www.seriouseats.com/recipes/2010/12/bottled-negroni-cocktail.html

Cheers!