For my step daughters 12th birthday we told her she could have whatever kind of party she wanted (since that was her last "kid" party) and after extensive research she decided on a Baseball Party. For the invites I used a computer graphic of a baseball and found a fun party invite to be sung to "take me out the ball game" it went: "Come join us for a party - Come join us for some fun - Come to \*\*\*\*\* 's birthday baseball game - she's turning 12 and wont stay the same - Oh its root root root for the birthday girl - if you can't come its a shame - for its one! two! three! times the fun and \*\*\*\*\*'s Baseball Game !!" I reserved one of the towns baseball diamonds (this was free for me check with your towns parks/rec dept), and encouraged everyone to dress comfortable in there favorite baseball attire and bring any equipment they wanted. (I also put a rain location on the invite and rented some sports bloopers tapes just in case - luckily it wasn't needed). I served ball park food vendor style - grilled hotdogs with all the fixings,unshelled peanuts, cracker jacks, popcorn, nachos and giant pretzels (which were good but alot of work and would recommend the frozen ones to anyone who wanted to attempt). My husband got the baseball game going with the older kids (ages 10-22), while younger kids and family members watched and ate and then they switched and the older kids ate while the little ones and parents played t-ball - everyone ate ball park style in the bleachers-then we all gathered and had a baseball diamond birthday cake with lots of little plastic baseball guys on it and then did presents. After we did a baseball pinita (which I made using one of the those bounce balloons, old newspaper, flour and water and then painted to look like a giant baseball)and pitched to the kids having them use one of those plastic t-ball bats (it took 15 trys for them to break it) and looks awesome when someone drives it home. I bought baseballs for a $1 a piece from my local walmart and gave each person a marker and ball to sign autographs with so the kids left with a cool momento and alot of pinita candy, bazooka bubble gum and unshelled sunflower seeds(you can also request free baseball cards from most teams but it takes almost 6wks to get them (I didn't do it because I didn't have 6wks) but if you have more forthought then me go for it. The best part was the whole party cost less the $100 and was fun for all ages - because it was something everyone could do and and the older kids were able to play without having to wait for the little ones to take there turn.