Countdown / Automatic Recalc ?

so...i'm writing a program in Excel for my friend who works at a small pool hall. I've created a countdown (initiated when the user clicks a table) and some other cool stuff.
I posted a pic of the excel file here: http://jeremy.haynie.googlepages.com/rackems.jpg

so right now I've got the countdown cell (17 min. 15 secs in the pic) as a normal worksheet cell...now - start time. and i've got a macro running every x seconds which makes the cell look like a countdown. I've got vlookup functions bringing back the dollar amount.

here is the code i'm using to recalculate and the one to close the workbook. Basically, I've got the recalculate stuck in a loop until the user closes the workbook.

Is there a better way to do this Sometimes the workbook will automatically reopen because the recalc macro runs again.

Sub recalc()
If stopp = 2 Then Exit Sub

Dim wksht As Worksheet
For Each wksht In ActiveWorkbook.Worksheets
wksht.Calculate
Next wksht

update = Now() + Sheets("lookups").Range("updateinterval")
Application.OnTime update, "recalc"
End Sub

Sub tclose()
stopp = 2
Application.Wait (Now + TimeValue("00:00:05"))
'allows time for "recalc" to stop
ActiveWorkbook.Save
ActiveWorkbook.Close
End Sub