Indoor Olympic Games:
Gymnastics Displays - get the children to come up with a gymnastic/dance routine (give them ten minutes or so and a piece of music) - get them to perform.

Obstacle Course - set your room up to be a mini obstacle course - such as having to crawl under chairs or a table, jump over the settee etc. (Play safe!)

Paper Airplanes - Create and then throw your teams airplane (could be an individual knock out challenge or a team challenge)

Dance offs - get the children to have a dance off against each other (could be on the console) 

The Great Egg Drop - give teams lots of resources such as big plastic bottles, string, paper, tape, glue etc. and an all important egg. They have to then design a carriage for the egg with a parachute - the egg has to survive being dropped from the stairs to the ground by an official.

Outdoor Olympic Games
Badminton/Table Tennis/Tennis - Play the game like the pros - doubles, singles or even mixed doubles. Keep the scores and tally them up at the end to see the points for each team.

Races - you can have lots of fun here. Three legged races are lots of fun, egg and spoon races, sack races or even relay races are great too. This could be a great way to round off the events.

Silly Races - a great opportunity to make the children get in the mood. Create an obstacle course which will get them to have fun - include dress up items, hula hoop tasks, ball throwing at the end and knocking down cups. The fun will never end (make sure to get the adults to demonstrate)

Water games - throw and catch the water balloon in your team. See which team can keep it going the longest. Or using a squirting gun, squirt the teams boat across the pool and back again. If you have a paddling pool/pool you could fill it with balls that are multi-coloured - each team has to jump in and get their teams balls - first team with all their balls wins.

Balloon Dodge - If you have brave children that don't mind water balloons you could play a game of water balloon dodge - standing on either side of a line the teams can only have a certain amount of balloons in a bucket behind them. They have to run from the line and get a single balloon each and then throw it at the other team. Any hit means your out!

Long jump - if you have some great jumpers in the group then the long jump could be a great idea. Use a tape measure to measure the distance and award points accordingly.

Football - Penalty shoot outs - give each child a chance to score against an adult in the penalty shoot out. Keep it going until one team wins or you could give each child 3 attempts and score them 10 points for each goal (keep a score chart).

Bean Bag throwing - have a go at throwing a bean bag in to hoops or baskets to score points. The further away or the smaller the hoop/basket the more points they can get.

Bowls - get the children to have a go at bowls by rolling a ball to try and get it the closest to the smaller ball. Give each team a certain amount of attempts and give them points such as 3 points for furthest away and then add points to it until you get to the closest ball. Better yet, if you have a target sheet that you can lie down - your job is done!