here's one for a watermelon cocktail.  the original recipe called for brown sugar, but i substituted strawberries instead.
one medium size watermelon, chopped
a handful of strawberries
lemon juice
mint
squeeze desired lemon juice into large pitcher; throw in the mint and muddle.  blend strawberries and melon in batches to desired thickness.  pour the puree in with the lemon juice and mint.  it keeps for a couple of days.  add vodka right before serving.  
been enjoying this all summer.  very refreshing.