Around halfway through level one, when you are jumping high over the river, and before you start jacking strongs, there should be a blue portal you come across. Press B next to the portal to enter it.
Once you are in it you have a certain amount of green orbs to collect (5000 points worth in this particular challenge) in a certain amount of time. The moment you start rush to get the green orbs in from of you and any of them you see. After a few seconds some will start spawning by the crates up ahead. Do not smash the crates. Go for the bigger green orbs for more points.
This may take a while, but you can always retry it but just entering again or replaying it at the level menu.