Olivia, it's hard to tell the joke in writing, but I'll try. Basically each government branch can be represented by a finger on your hand:

1. Thumb = Department of Transportation (as in hitchhiking)
2. Pinky = Department of Health (as in picking one's nose with the pinky finger)
3. Index = Department of Education (how a teacher points at students)
4. Ring = Department of Treasury (that's where rings are worn)
5. Middle = IRS or whoever the revenuers are in a particular country (this is pretty self-explanatory though it helps to make the appropriate gesture ;) )