[_b8r0]

> just trying to think what kind of cool thing to provide in return for the generous donations.

It seems to me that people are donating because you've earned it. If you really feel a need to give back, perhaps the gift of education would be better. W. Richard Stephen's TCP/IP Illustrated is a great book, but looking long in the tooth these days. I'm sure you've forgotten more about TCP/IP than most of us have learned, but perhaps a book on TCP/IP by a guy that wrote a stack would be a good start?