Switch
Kids often enjoy comparing two seemingly identical pictures and figuring out what's different from either picture. This indoor game does just that, but with actual players instead of pictures. Divide the players into two teams, and have one team go first by putting on various clothing items and accessories. Let the other team see the finished look after the first team has put on all of the items. The second team then leaves the room as the first team switches clothing items with other teammates. Bring the second team back in and have them guess which things changed since they left. Record how many guesses the second team made correctly. Then, have Team B do the switch for Team B to guess. Whichever team made the most correct guesses wins.
Freeze Dance
This game allows children to dance and act silly within the confines of a large indoor space. The game begins when you turn on some music and let the kids dance. Then, as soon as you turn the music off, the kids all have to stop dancing and freeze in the position they last held before the music shut off. For instance, if one kid has their arms in the air, they have to hold that position until you turn the music back on. Whoever fails to freeze entirely gets disqualified. The game ends when only one player remains on the "dance floor."
Four Corners
The classic game takes place indoors, with each corner (numbered from one to four) serving as a base for the players. Pick one player out from the group of children to be the leader. He has to stand blindfolded at the front of the room with his back turned to the rest of the group. On the count of five, the rest of the group has to find one of four corners in a room to hide in. The leader has to try and eliminate the most kids by picking a corner he has determined to hold the most players. He picks a number after the five seconds have passed, disqualifying all of the kids in that corner from the game. This process continues until only one child--the winner--remains; thus becoming the next leader.