A couple beers that I brewed a while back are really starting to come into their own. I brewed a NW pale ale kit from Brewcraft in the first week of June that I thought was too sweet, but over time has really improved. The hop flavor is much more pronounced and the maltiness seems to have subsided, which is odd because I always thought the opposite would happen. Not too many of these left since I've been drinking quite a few of them over the past 3 weeks (after hardly drinking any the first 3 months).
Same can be said for a belgian witbier kit from Midwest I made back in April. Initially, it tasted really bad, IMO. Almost sour, and didn't really have any belgian flavor. After about 5 months it's become one of my favorites. You can really taste the orange peel now and it doesn't have a hint of sourness to it.
I dunno if I'm doing something wrong or if homebrew really does improve over time but pretty much all the beers I've made (especially the two listed above) have improved after a couple of months. FWIW, these are all extract brews, and I used the late addition (roughly 5 minutes left in boil) method.