Looking for an API that rolls on a timer

I'd like to set up some timed rolls for stuff like random encounters.  Are there any APIs that will roll X dice per X minutes?  Then, if number rolled = X, roll on an encounter table?  That last part isn't necessary really, I can roll on the encounter table but I just like having Roll20 keeping track of the time spent in a dungeon and rolling encounters for me at regular intervals.  It also would be helpful for timed stuff like the geisers in White Plume Mountain.

Are you talking about real world wall time, or some sort of in game time tracker?

Real world.  Here's an example text from a module: Check once every 10 minutes for random encounters by rolling a d12; an encounter occurs on a roll of 1. If an encounter is indicated, roll a d6 and refer to the table below. So, I'd love to have it so I get a whisper every 10 minutes with a roll and if it is a 1, roll on an encounter table. Another example: The ceiling is 50 feet above the level of the platforms. The cave floor is 50 feet below. Two spots in the mud are the locations of geysers. The northern one erupts once every 5 minutes, the southern one every 3 minutes When they enter the geyser room, I would start a clock that lets me know when 3 minutes and 5 minutes have elapsed.I'd stop it and have them roll DEX saves, etc, then restart.   I could probably use the same API as the encounter and just disregard the dice so long as I can label them 'Geyser 1', Geyser 2', 'Encounter', etc.  

hmm.. definitely doable and not terribly hard.  The hardest part is the interface.  

cron might be able to do this.