An easy one to start you off:
Which How I Met Your Mother Character Are You #1? (I'm a Lily)
You will be prompted to sign up for a BuddyTV account (if you don't already have one) to get your results though, so if you don't want to do this, try the quiz below)
Which HIMYM Character Are You #2? (this one tells me I'm a Ted)
No sign up, but slightly longer
And some character-specific quizzes:
Finally...I challenge you to pose a trivia question in comments and see if you can stump the other Reelers! If you know the answer, you can write it as a comment and then pose a new question!
Give it a try. It'll blow your mind hole. Someone can start by telling me which character said that!