You could do this in an InfoPath form displayed as a webpart, I'd guess? You could just query the list - use a count formula with a filter to count just the passed tasks, and count w/out a filter to get the total.... See the attached sample. I'm using main data source fields, but you could add a data connection to your list and do something similar. Save the file locally, right click and select preview and you can try it out.
Hilary Stoupa
