We've also installed some mods to make it more fun. Just off the top of my head is mcmmo which allows you to level up skills the more you use them. All of the skills are Excavation, Fishing, Herbalism, Mining, Woodcutting, Axes, Archery, Swords, Taming, Unarmed, Acrobatics and Repair. Most of the skills have nice passive bonuses or procs. You can see your level in these skills by doing /mining, /<skill name> or /mcc for all the commands the mod offers. Another is Towny which allows you to set up nations/towns for a cost of in-game money. The shops allow you to get in-game money, you can buy/sell many items so don't spend it all in one place! Do /money to see your balance. There's the usual teleports like /spawn that's close to the mall and /home (need to /sethome first) for easy travel. Worldguard allows an admin to protect areas of the world from greifers and explosions. There's probably others but it's all i can remember. Some mods are a work in progress and Kei is working on them.
