Set up a free clinic for kids in the area. You can let the clinic last a week, do it over a weekend, or even just a one-time all day event. Have players from the high school team divide into pairs and take groups of kids to work on certain techniques, catching, running, throwing, pitching, etc. After a certain amount of time rotate the groups so that the kids get to work on each technique.
At the end of each session, at the end of the week, or the end of the day ? depending on how long your camp is, have a time to set up a few contests. You can have a home-run contest to see who can hit the most out of the park. For younger kids you can have a contest to see who can simply hit the farthest. Have a backwards baseball game ? where batters run the opposite direction than normal.
For the silliest game you can play dizzy baseball. Instead of pitching, set up a tee-ball post. Have batters come to the plate and place one end of the bat on the ground. Putting their forehead to the other end, have them spin around 10 times, then stand up, hit the ball off the tee and run the bases. Chances are good that there will be more laughing than playing!
To make this baseball fundraiser a success you can sell sports fundraising candy as a concession, or even have a table set up for parents to participate in a scratch card fundraiser. However your team decides to raise money this year make it fun and creative.