Best EXP for some classes lvl 30+ : City of Heroes - Submissions

This works best if you are an assault blaster or fire tanker, but other classes might work too. Go to Crey's Folly (lvl 30+ hazard zone) and look for The Swarm. Just walk in the middle of them and let loose your fire aura from fire tanker or Ignite from assault blaster. The swarms go down fast and do almost no damage. You can go further in and take out the lvl 37+ swarms for great xp. You get about 400+ xp per mob and they usually come in packs of 8. That's about 3200 xp in less than 10 seconds.

Also, there are some snipers hidden around corners of buildings. You can Ignite the ground under them and they won't chase after you. Keep burning them and they will eventually go down. They give 1500+ xp.