Remember that classic arcade game "Track and Field" from the 1980's? Well imagine it on a phone and you've got Pentathlon. I'm a sport's junkie so I really enjoyed this game and the only thing you'll have to worry about is how much your thumb can take.
The Pentathlon challenge consists of 5 sports - 100 Meters, Long Jump, 110 Meters hurdles, Javelin and Swimming. In each event, you compete against 5 other athletes in your bid for the gold medal. The graphics and sound are straight out of the 80's - anyone who hung around amusement arcades back in the day will recognise more than just a few. Don't underestimate the damage this game can do to your keyboard though - especially hurdling which requires lightning fast fingers plus an extra one to jump.
The major downside was the level of difficulty which I found way too high. I didn't manage to win a single event although this didn't really ruin my enjoyment of the game. The Javelin in particular proved completely impossible although if you've got a few hours on your hands, this game will certainly kill them.