This year, the Forest is playing host to Software Freedom Day, Saturday 20th September. More details to follow, but the idea is that a team of SFD volunteers will be in the cafe to demonstrate Ubuntu, help people out with installations, give out some disks and generally promote the idea of free and open source software.
If you are interested in helping out, or want more details from the horse's mouth, check the EdLUG mailing list.
I won't be there, but I'll have some posters up in the next few days for this cool event.