I've been running into the same problem that Jade mentions above and the problem is exactly what Jeff says. Something is hanging the server and every 3 minutes another keepalive cron is spawned because the previous one is still waiting for the 15 minute timeout.
To prevent this I simply added --timeout=20 to the wget script. I'm not sure if this timeout threshold would be good for everyone but we should add some sort of timeout to the script and/or advise people to make sure the timeout they set is shorter then the length of time between cron runs.
