My $0.02:
I agree with TimR in that there are two things going on: developing a rhythmical sense and an intellectual understanding of notation/patterns.
A couple other ideas for developing a rhythmical sense- there are 2 kids' toys on the market that are great for this. If the adult has kids, there is a reasonable chance that they already exist in the home. They are:
Bop-It! - a handheld game which calls out one of 3 commands in a rhythmical fashion. The commands are "bop it," "twist it" and "pull it". The device is about 12" long, with a large button in the middle for bopping, an extension to one side for twisting, and a longer extension on the other side with a pull handle at the end. As the unit calls out the commands, you hang onto the unit, and execute the commands with one hand or the other (both hands need to cooperate). You get jeered if you don't execute the command in time with the beat. It's great for coordination and rhythm. It's pretty cheap and it's fun for most anyone.
DDR: Dance, Dance Revolution. This is a game for playstation, xbox, gamecube, and ? You need a dance mat as your game interface. This is a maybe 3 x 3 mat, with up, back, right and left arrows on it, as well as some game control buttons. The software gives you techno dance music (pretty bad stuff IMHO) and a display showing the dance arrows. The arrows (zero, one or two per "line") scroll up the screen so you can see what's coming, and when they reach the top you need to execute the move with your feet exactly on the beat. So, standing in the center and with commas delineating the scroll lines, it might go ">, <, <>, <>." And you would probably put your right foot on the right arrow, then your left foot on the left arrow, then jump onto both arrows, and again jump onto both arrows. You need to do this right on the beat of the music (which coincides with the arrow hitting the top line). Your are rated on how exact you are (Perfect, Very Good, Good, Almost, Boo). It's challenging. It's great exercise. The mats are pretty cheap, but the game consoles are not.
Both these games are great for kids and adults who need a better sense of rhythm or coordination. They are both somewhat humbling, so they are also good for oversized egos

A search will provide you with pics if you're interested.
Karen