Here's some background and inside jokes to help fill in some of the gaps for viewers who don't watch both Philly-based shows.

Here's a look at our real-time thoughts on tonight's crossover between FXX's It's Always Sunny in Philadelphia and ABC's Abbott Elementary.

The "It's Always Sunny in Philadelphia" crew is headed to "Abbott Elementary" in the first of two crossover episodes. The highly anticipated crossover episode will see Charlie (Charlie Day), Mac (Rob McElhenney),