How to catch and stop some election fraud:
http://www.youtube.com/watch?v=DaEECHjWptU
Video the vote. Bring cameras. Record what happens. Find out how to complain about problems, and do it ASAP.
How to hack the vote:
http://arstechnica.com/articles/culture/evoting.ars
A description of how to change the results of the next US election nearly untraceably.