For my son's 2nd birthday, it was August and VERY hot. So we had what I referred to as a Summertime Fun birthday.  For the invite I took a picture of him (I used black and white because I like the look) sitting in his kiddie pool eating a popsicle. I put the 4x6 picture on one side of 5x7 card stock with the wording on the opposite side.  I used bright colors; I bought a pack at Michael's, they come with the envelopes. (since popsicle colors was my theme).  It read:  "Popsicles and Water Fun...These are TWO of Andy's favorite things...Please join us as we celebrate Andy's 2nd Birthday"...with party info. At the bottom I had a caption:  "Be sure to bring swimsuit or change of clothes, towel and plenty of sunscreen". For the party, I just served simple "summer" food, pb&j sandwiches for the kids, store bought crossaint sandwiches, chips, and a big bowl of fruit. The table looked beautiful!  Sometimes simple looks nicer. Small water bottles and juice boxes in the kids ice bucket and waters and sodas in the adult ice bucket.  During the party, the kids alternated between our kiddie pool, filled with various toys, to the slip n slide, to our swing set to our playhouse.  Since it was set up like "stations", it was nice because the kids rotated as they pleased.  After eating, we brought out watermelon slices, then a bit later the cake, then a bit later the popsicles.  For favors, I just gave out beach balls.  The babies received some sort of age appropriate toy I found at either the dollar store or big lots.   The adults and kids alike very much enjoyed the party. The kids' ages varied from zero to 10 and I think they all enjoyed it equally as much. It was so simple my husband and I really enjoyed ourselves too!  It was the best party we've given, since we enjoyed it so much and really the guests did too. Again, so simple yet perfect summertime fun!