I guess there's an OK chance that you've actually seen this video, since it's had 500,000 views on YouTube in 2 days, but I'm posting here because I thought it was pretty funny.
It's a parody of the very popular video (over 250,000,000 views) "What Does The Fox Say?" which tries to answer, in song, the question of its title. That video/song was created by the Norwegian band Ylvis. Extremely silly, very catchy, and lots of fun.
The video I am embedding below is called "What Does The Spleen Do?" and it was created by a group from the Harvard Medical School. It also attempts to answer the question of its title -- with much less success, but with all the catchiness of the Fox song.
This is, of course, very relevant to Follicular Lymphoma; stage IV lymphomas often have spleen involvement. Dr. R taps on mine regularly.
For the record, the spleen really is a blood filter (which is why B cells can collect there), and plays some other roles in immunity. But what's more important, after you watch the video, is knowing what it doesn't do.