Catch her while she’s not having a psychotic moment and give her some money! Yes, Britney Spears will be appearing on the March 24 episode of “How I Met Your Mother.” Spears will be playing a “mousy” receptionist named Abby. Haha! Putting Brit-Brit in a low key “semi-unattractive” role is comedy gold. Set your stopwatches to see how long this latest comeback will last.