I've got spreadsheets for stuff like the sale value of vehicles in GTA Online, the stats for every armour piece in Dark Souls 2 and a colour coded chart showing what loot is on which mule in Borderlands 2.
By the time we stopped my wife and I had a 200ish page binder full of WoW drop tables, gear stats, dungeon maps, build plans and spec charts. We also had the continent maps including flight paths and resource nodes blown up, printed and framed on the wall. To top it all off, my wife built the guild's website and DKP tracking system while I designed and posted boss strategy diagrams :P
It was the best of times, it was the worst of times. But seriously, mostly best of :)