Anything about my app -- shouldn't matter to you, but I need a nice way to graph # of events per day / hour / minute and drill down into the details of each one

Anything about my app -- shouldn't matter to you, but I need a nice way to graph # of events per day / hour / minute and drill down into the details of each one. Perhaps like Splunk or Loggly but much cheaper / less enterprisey. Simple way to know if certain metrics (code errors, # of new users, downgrades, 404s, etc. are going up or down over time)