Yes. On the server side you can use any class in the CLR.
However, I don't believe your question was intended to be as broad as you
made it. What, exactly do you want to do with a timer on the server side?
Remember that an ASPX Page class exists for a very short period of time
(milliseconds for the most part) on the server.
--
HTH,
Kevin Spencer
Microsoft MVP
..Net Developer http://www.takempis.com
Complex things are made up of
lots of simple things.