Do you need a visible timer for your audience? This timer is easy to use, low lag and you can modify the object's appearance as you like. This is just 2 prims.
This is Version 2 of the timer. You can find an enhanced version 3 here.
The timer object is easy to use and a usefull tool for lectures, discussions and classes in SL.
Rez the timer object in your classroom or conference room. It will show 00:00 at startup.
If you are in a high lag area, click on the object and choose "hi-lag" from the menu. This will cause the clock to update the display every 5 seconds instead of every second.
To start the clock just say the desired countdown time in the chat in channel 100.
For example:
/100 1:00
will give you a 1 minute countdown
/100 2:30
will give you a 2 minute and 30 second countdown
/100 20
will give you a 20 second countdown
After the set time the counter will say "Time is up!" in chat and it will play a ringing bell sound.
if you don't want to play the bell sound at time 00:00 you can choose "no-sound" from the menu.
Deceptive
If you are going to market this as a something you can modify than it'd be nice if that permission was turned on for the scripts as well. Buyers don't waste your time or money with this purchase.