VBA provides an Evaluate(string) function that does what you want but it is not directly accessible from the worksheet. To make it accessible you can write a VBA eval function like this :

Function eval(func As String) 
    Application.Volatile 
    eval = Evaluate(func) 
End Function
You would use it like this:

=eval(H8)

Note, though, that it is volatile, as it wouldn't know when to recalculate when necessary, so it rather defeats what you are trying to do.

Hope this helps.

Pete