Today's cheap and nifty idea is to find a new way to love and use old vintage clocks. For this purpose it is better that they are broken but you can remove and replace the battery after the event if you want to keep using them (maybe not all in the same room as that might be a bit strange, although very eye catching people might think you are a very anal clock watcher!)
I always think of clocks as having different personalities. It probably stems from watching and being hooked on Disney and cartoons when I was younger, but the taller slimmer clocks remind me of being a bit austere and jittery, whereas big round squat clocks don't care what you think of them and would walk off down the pub if he had legs rather than just hands (ha!)
I thought up the idea of using clocks on tables to indicate the table number. Now you will need digital clocks to do anything over 12, but 80's in increasingly being seen as 'vintage' so I am sure in only a few years time there will be some Jason and Kylie esque themed dos!
You set the time to the hour to let guests know where to sit, hence you need the clock to be out of action so that people do not get confused. This will add interest to the table and is really quite cheap to do, especially if you are using other vintage items like tea cups etc. You should use a mixture of different clocks, I think the wooden ones are easiest to come by and some often have pretty patterns carved into the wood or painted faces. You will almost certainly find these at car boots sales and charity shops.
I found this selection of burly and elegant examples of Ebay, all under £10 apart from the Baroque one above which is £16.