Tie a magnet to the end of a string and then tie the string around the player's waist so the magnet dangles down between their legs about a foot off the ground. Around the room scatter the metal objects and make some of them harder to reach by putting them in receptacles, etc. Set a time limit and the player must see how many they can stick to the magnet without using their hands. Player with the most wins.

Scoring is, as always, completely arbitrary, you can award only the winner, score points per metal object, or award points on a sliding scale from most to least. Decide how you wish based on the number of players.

If you have more magnets for can set a few players up and once and have them compete.

Make some of them harder to get to and worth more points. Inside empty tissue boxes, under plastic cups, so they have to go inside or knock over something over to get to the metal objects. Even put some up stairs or on a table, etc.