The one scene that I vividly recall is that both Kurt and Blaine attended a halloween party (possibly at Brittany's house?) and Kurt was dressed as the Tenth Doctor. Blaine had a huge crush on Kurt and basically swooned when he realized that Kurt was dressed as the Doctor. I know they were friends before that, but I can't remember if they both went to the same school or not.
The fic might have been Blangsty, as I've always been drawn to those, but I'm not sure. That's it. I know this isn't a lot to go on, but I'm interested to see if anyone else can remember this one.