A festival grounds is a lot assignment introduced in The Sims 3: Seasons. They typically replace the largest park lot in worlds released by EA, inserting many festival-related objects that change by season. They are controlled by a seasonal lot marker.
Seasonal lot marker
Festival grounds can be built with the use of a seasonal lot marker, which causes the lot to change throughout the year by setting certain objects to only appear during these times. It can be used on any lots, including residential lots. Using the marker you can set the spring, summer, fall, winter, and construction seasonal item as and set to the common phase for items all year around. The marker does not affect features implemented by Build Mode like walls and roofs however, and will always stay in the common phase. You can also name the seasonal festival for each season.
Each season, the theme of the festival will change.
Spring - In Spring, the main theme of the festival is love. You can find objects like the kissing booths, the love tester, and the spring dance floor. For children, there is an egg hunt as well as roller skating, and maybe some playground equipment and the usual face painting, and seasonal greeting card tent.
Summer - In Summer, the main theme is Summer fun. In this case there are objects like the soccer goal, a water balloon arena, snow cone machines, the hot dog contest, and roller skating with face painting and greeting cards.
Fall/Autumn - In fall or autumn the theme is spooky fun. At this festival you can enter the haunted house, pick pumpkins at the pumpkin patch, join the pie eating contest, have your face painted or take a greeting card.
Winter - The theme in Winter is Winter fun. In this festival you can snowboard, go ice skating, join a snowball fight, possibly relax in the hot tub, or the usual face painting and seasonal greeting cards
Construction - The phase between each season. A usual park with grills, picnic spots, and picnic tables.