Like- In Time With You or 9 Ends 2 Outs. Are there any other dramas where friends fall for each other? EDIT: I've seen Proposal Daisakusen and Reply 1997 also.
Reply 1997 Proposal Daisakusen Both are awesome, all about long term friendship turning into love.
Reply 1997 (totally amazing!!!) Lovely Complex (Maybe) Operation Proposal That's all I can think of for now
Buzzer Beat? I mean.. they're friends, right? xD buzzer beat is the only thing i could think of
love the bro-love in Sunghyunkwan Scandal. they are really cute
Bu bu jing xin/startling by each step This cdrama very complex in complete love story :D (not only 2 friends)