Reply #4: Recent South Park - THIS explains it

[Serial Mom]

Goobacks
Original Air Date: 04-28-2004
Humans from the year 4035 are arriving in droves in South Park! Everything gets a little too crowded when people from the future arrive through a recently discovered time portal. When the boys try to earn some extra money, the time immigrants, who are willing to do the same work for next to nothing, take their jobs.

This was a really good episode - sad in some ways cause sometimes those "innocent" little 8 yr olds are more honest than our government!