I'm up for post swapping for my two forums in my sig, but they are quite specific subjects, if you have a knowledge of either sport post away and sent me a PM when you've done with your forum URL and i'll return the favour.
If all else fails, try seeding your forum with drama threads. Admittedly, this only works for general entertainment sites and some adult webmaster boards. If the forum is focused on "serious" topics, leave drama out. Regardless, nothing boosts participation more than troll drama.
Our DP member, yfs1 has written a nice article on Forum Boosting ... Have a look! http://www.yfs1.com/2006/boosting-a-forum-a-bit-of-advice-and-some-methods.html Abhishek
I just thought I'd add that I have a celebrity and music forum, I've just manged to buy a Coldplay (Famous Band) signed sheet music from ebay that I'll give away to the first poster that reaches 200 good posts (I'll delete spam) hopefully that'll generate some interest. It's not going too badly so far as I already have around 500 posts in the forum and traffic is getting better all the time.
There are also forum posting services available to help you get going. I have not used them but it's cheap enough to be of use.