URL based redirect...

That should work for you, but you are doing a separate string allocation in each of the if/elseif's. If I were you, I'd go with the switch route (just my own preference. And since, you are using the same case for each of the conditions, a switch is extra-easy to read. Either way should work for you though. You pick what is easier for you to maintain.

Here's the switch version of your iRule:

when HTTP_REQUEST {
  switch -glob [string tolower [HTTP::uri]] {
    "/calendar*" -
    "/smd/student/2008*" -
    "/cgi-bin*" {
       pool URMCPublicExclusion_HTTP_Pool
    }
  }
}

The -glob argument is for file-type globbing (wildcards).

You can check out the syntax for the switch statement here:

http://tmml.sourceforge.net/doc/tcl/switch.html

Click here

And, yes, if none of the conditions are met, it will default to the default pool assigned to the virtual server.

-Joe