There are several Minecraft mods that allow users to create interactive mini-game elements. There are too may to list in one topic. But there are some basic ones that cover a lot of area.
Mini games are not only fun to make, they add a lot of spice to game and encourage social activity.
1. Start -> Checkpoint -> End block functions
In the past I saw this implemented with signs. When creating a sign you would group them to the a game by name and assign the functions.
Start -> begins the race
Checkpoint -> required to be hit before the end
End -> ends the race and reports the user’s time
People would place this in mazes and parkour games to time the race or use them for having various other crafting/gathering races. In more advanced MOD’s, if a player died after a check point, they would rez at the last checkpoint. That was especially good for parkour.
2. Capture the flag
In the past I saw this implemented with signs as well. One blue and one red flag as well as one blue and one red destination. On top of that, there was a command to start the game and local chat announcements which flags left their bases and when they were reset,
Naturally this one is a PVP based system, so it would have to occur in a PVP area, even if that was just a beacon area.
