Lily Aldrin (Alyson Hannigan) is a kindergarten teacher and an aspiring artist. Lily was originall engaged to Marshall before they broke it off for her to try and be an artist in California. However, she returned to him after her fellowship ended and the two quickly married by the end of season two.
Barney: Guys, I just tasted an amazing caterer.
Lily: We already have a caterer.
Barney: Oh right! You're getting married. [to Ted] You see what I did there?
Robin: I've never been to the Empire State Building before, but I'm glad I waited.
Lily: I haven't been to the Empire State Building either, but I'm glad I get to go with my fiancÃ©e.
Marshall: And I signed an abstinence pledge in high school, and it's totally cool. Also, stay away from drugs... except pot.