WARNING - RANT AHEAD!
In HeartGold and SoulSilver one of the ways to up the rank of your trainer card is to become champion in the Pokeathelon. One of the requirements to do this is to beat the high scores in all 10 events.
The Pennant Capture event's high score is 35. That means you have to get 36 or more pennants (flags) in 1 minute by using 3 Pokemon.
There's a problem though: each Pokemon can only hold 9 pennants total before they must return and let the next Pokemon have a run. This takes up around 3-4 seconds of valuable time.
Also, the other teams' Pokemon can steal the pennants that your Pokemon has if they run into the backside of your Pokemon.
To make matters worse there are obstacles. AND umbrellas hiding some of the pennants. It really doesn't help because the other Pokemon running around are usually much faster than yours, and the pennants take a while to regenerate.
EDIT April 14, 2010
I finally beat this stupid thing! I ended up getting 40 flags with Arceus, Feraligatr, and Pinsir!