There are a few good topics out there depending on the assignment. If there is any presentation involved and you are the type who likes to metaphorically **** in people's morning coffee there are a lot of hot button issues. I always found that taking a more extreme stance makes for a more fun and exciting position. I recommend:

-Prayer or religious practices of any sort in the class room
-Cost, nutrition and access standards placed on food served in public institutions (schools)
-Nation wide speed limit on interstates with a fuel economy angle
-Health care
-Euthanasia and/or assisted suicide
-Abortion
-Same sex rights