In "Customizing Roundup/Adding a time log to your 
issues" - point 4:

The function "totalTimeSpent" in this example takes 
one argument, but I think it will be called with two - 
with an instance of TemplatingUtils as the first 
argument, and then the original argument from the 
example code.

I did't run this code, but have a similar situation.
This is a part of an "extension" script (Taken from 
wiki LinkFormattingExample and converted to 0.8.0 
following the said example):
...
def localReplace(*args):
    print "ARGS:", args
    message = args[1]
    return CustomTags().replace(message)

def init(tracker):
    tracker.registerUtil('localReplace', localReplace)

This extension is then used in the page like this:

<pre tal:content="structure python:utils.
localReplace(msg.content.hyperlinked())">content</
pre> 

And it prints on the console:

ARGS: (
 <roundup.cgi.templating.TemplatingUtils instance 
at 0x0105FA30>, 
 'This is a change note.'
)

So I guess the signature of the original function in 
the example should be:
  def totalTimeSpent(utils, times):
while now it is:
  def totalTimeSpent(times):