If you input a BPM for a song, this website will display an animated cat bopping its head to the rhythm.
Don't know the BPM of a song? Try using a search engine with a query like "[song name] bpm". Or, you can use an external website to tap it manually or detect it automatically with a file upload.
Examples: Pure Crystal @ 170 bpm, Apache @ 115 bpm, Run Away With Me @ 119 bpm, Deadlocked @ 135 bpm