At Host Havoc, all of our Minecraft servers support the use of mods. Please take into account that when using mods, we cannot guarantee their functionality or be held responsible for any issues that they may cause (data loss, crashes, etc.). It is recommended you first back up your saved data prior to installing new mods.
Forge
Forge allows you to load mods onto your Minecraft service.
Cauldron
Cauldron allows you to load mods and Craftbukkit plugins onto your Minecraft service.