Aside from Madrigal I have played and/or NPC’d and/or staffed the following LARPs (at least once and in no particular order):

inkpen
Aralis1 & 2
Arcane
Atlas Adventures
Atlas Agenda
the Calling
Cottington Woods
Endgame
Epic
Hope’s Crossing
Invictus
Isles
Knight Blades
Legends
LIONE – End of Seasons & Veneration
Lovecraft’s Legacies
MASI – the Exiles Saga and Roanoke
Mirror Mirror
Mythical Journeys
NERO Mass
NERO Hartford
NERO Boston
NERO Atlanta
NERO Pittsburg
Otherworlds
Prophecy Games 1-3
Radiant Dragon
Realms
Realm of Requiem
Second Dawn
SOLAR – Everhate
Steam and Cinders
Terres Rising
Twisted Crown
Valiant
Witchwood