Lots and lots of cleaning, including Mr. Maellard's limo, windows, sweeping stairs, etc.
Painting the house's sides (appears briefly in "Benson Be Gone").
Lawn mowing, there are very strict guidelines even up to 1 inches in order to prevent lawsuits on games in grassfields.
Cleaning the fountain.
Transporting rocks to available storage space.
Cement laying around square areas.
Raking the leaves, hedgeclipping, picking up litter.
Pouring water over many masses of dirt or leaves that make things filthier than it needs to be.
Setting up the chairs.
Snack Bar duty.
Driving away someone who thinks he's a knight who made a fortress out of mattresses and refuses to leave the park.
Clean up anything that was damage of property.
Cleaning up graffiti.
Maintenance to the Zen Garden.
Picking up roadkill.
Cleaning up the Golf Cart.
Hosting concerts.
Getting rid of the possums in the attic.
Raking the sand in the park rock garden.
Fixing the cart (accomplished by Skips).
Park Events
Annual Barbecue.
Appreciation Day.
Guy's Night.
Game Night.
New Year's Masquerade Party.
Annual Pie Contest.
Trivia
The park employees are constantly raking up fallen leaves despite the trees appearing green in every episode.
The park is either demolished or severely damaged by Mordecai and Rigby, which is a running gag throughout the entire series.
As the full view of the park indicates, the park seems to be in the center of town.
The size of the park is constantly changing throughout episodes, ranging from being a small square area within the town to a large valley-like expanse of land complete with forests.
The Park's address is Park AV 300.
The entire lawn is in constant need of cutting, as most episodes that feature any of the park employees maintaining the park and has at least two of them mowing the lawn.
Despite the park having many locations, there are rarely visitors at the park. This is possibly because there are many unusual events happening at the park, so no one wants to get hurt or involved.
There was, at one time, a raffle held every year. It may still occur.