Generally, it will take a day or two, it really depends on who made it. For all you know, it might not get updated at all, seeing as how all the mods are just volunteer work.
By the way, I don't know if you've heard about Adventurecraft, but it's possibly the best and most sophisticated mod out there right now. It was actually coded by the guy who made Recount for WoW, afaik ^^.
Here's a little snippet from the wiki:
'AdventureCraft is a total conversion for MineCraft, which turns the game into a pure adventure mode in which players cannot place or destroy blocks.'
For those interested:
You can design your own maps, or play maps other people made, and the amount of possibilities for puzzles, traps and combat scenarios is just...endless!
Wiki (you can download maps here) : http://adventurecraft.wikkii.com/wiki/Main_Page
Forum topic : http://www.minecraftforum.net/viewtopic.php?f=1032&t=128281
And no, I don't work for them or anything, the mod is just that damn good, I thought I would advertise it ^^. I can see the guy that made this getting hired by Mojang and the mod being implemented into the game itself.
P.S. Minecraft - best game ever, but only thanks to its community and the 50343123225 mods out there ^^.