Well theres the tales games Exodiea they're very popular in japan it usually takes me 50-100 hours to beat it even on normal. Then if you have a psp try Monster Hunter you can easily waste a whole day in that game. Monster Hunter Freedom Unite has close to 500+ hours in it and the recent MH is MH3U on the Wii U and currently has alot of people playing it. It's also another very popular game in japan.