Behavioral activation is basically doing things you enjoy so that you feel better. It's like going outside to play a fun game with your friends when you're feeling sad or bored. When we are feeling down or depressed, we often don't feel like doing things that we used to enjoy, but doing those things anyways can help improve our mood. So, behavioral activation is a therapy technique that helps people to do things they like and feel productive, which can ultimately help them to feel better. It's like a way to trick your brain into feeling good!