I really hope Jury nullification http://en.wikipedia.org/wiki/Jury_nullification becomes a bigger thing in this country..
Juries are not supposed to be rubber-stamps for the government and I'd urge anybody who is going to serve on a jury to learn about their rights and responsibilities before going.
If you think a non-violent person being charged in a marijuana possession case or other non-crime doesn't merit locking up, throw a wrench into the corrupt system and vote not guilty.