Well, according to
This thread on the Tivo Community forum (now bought to you by Tivo) it may or may not work depending on your software release.
Heres the relevant bit of that thread:
In reply to:
S-P-S-9-S - Toggles the Clock display in the bottom right corner. When you are watching LiveTV or a recording, this will show the time and where you are at in the recording. It's a toggle, so do it again to turn it off. However, when you turn it off, it doesn't disappear, you must go into a Tivo menu and return for it to go away. The Elapsed Time Indicator was removed in 3.0, to the general groan of everyone (it was very handy). They appear to have added it back to 3.2 on Series 2 boxes, but whether this becomes generally true is anybody's guess.
S-P-S-9-S means [while playing a program] press Select, then Play, then Select, then 9 then Select to activate the feature.
But, if your box is running 3.0 software, you may be out of luck