http://www.oovoo.com/ - video conferencing

www.polleverywhere.com lets you run polls at your seminar using SMS to participate.

www.dimdim.com is a free collaboration/meeting webtool.

www.printablepaper.net offers up PDFs of common forms: music sheets, graph paper, etc. for instant printing.

Funny site: www.dominos.com has this delightful pizza designer.

http://incompetech.com/graphpaper/lite/ - another graph paper generator