Just a few ideas off the top of my head:
1. Have an annual golf scramble, poker run, etc. and donate the proceeds to an existing organization like CCFA, HealingWell.com, etc.
2. Start your own scholarship fund and provide financial support to Crohnies who are wanting to return to school but can't afford it.
3. Contact/work with a GI hospital to either donate $ to Crohn's research or provide funding to help IBD patients who can't pay their hospital bills. A lot of places will let you donate money for certain uses only.
I'll see if I can come up with anything else.