Pilot Compensation - FAR 61.113

Hi All,

Here's a question for all the FAR/AIM experts:

Each year our childrens' school has a charity auction to raise money
for various events, services, and equipment. My wife had the idea that
I could donate a one hour flight, which could be auctioned for the
benefit of the school.

I'm thinking that I'm OK here, but wonder what the collective wisdom
may have to say. My rationale is this: I will receive in no way,
shape, or form any compensation for my flying, from anyone.
Essentially, I'm donating my expenses (rental, etc.) to the school and
I expect nothing in return. In reality, I'd go flying anyway on a nice
Saturday in April whether or not someone is tagging along with me. I
often take friends and acquaintances with me and again, I don't expect
or deamand any compensation from them. Is this any different?

Thanks for your input!

-CAE-