What sports were Leprechauns good at in high school ?

Gaelic Football.....................

Rugby players of course....

https://www.featurepics.com/online/Irish-Leprechau...

Oh there were quite a few. 

Which include:

Gold digging

Bare knuckle boxing

Rainbow sliding 

Endurance drinking with the Clurichaun

Spooking with the Far darrig

Shoe Lacing

Charming for Charms

Octave Tailteann aka Octave Olympics with the Banshees

Oilliphéist riding

Mountain climbing with Aes Sídhe

Dullahan head hunting

Playing Púca

You know for such small little fairy men. They sure do give the Tuatha Dé Danann a run for their money. Not even Saint Patrick could wipe them out. 

on line gambling

luck of the Irish

high jump and bog snorkelling