In honor of HIMYM ending and as a spin-off on Mr. Bee's Friends' thread, what's your favorite episode of HIMYM?

And if you say the last episode, we have the right to judge you.

I loved the episode where we found out about Robin Sparkles (and the slap bets emerged with it). My other one (warning: it's super random) is the one where Marshall and Lily have the double date with Robin and Barney then Marshall makes the post-get-together video. The video entitled "Cat Funeral" kills me.