foo(0) = "alpha"
foo(1) = "beta"
For i = 0 to UBound(foo) - 1
For those of you who don't know Visual Basic, the first statement declares an array with a range of 0 to 2 inclusive. UBound returns the highest valid index in the array (in this case, 2). For added fun, there was at least three layers of functions and several thousand lines of code between the two, and Visual InterDev's debugger refused to connect to anything. So when I innocently added a foo(2) = "gamma" and expected something useful to happen, all that actually happened was nothing.
In fairness, the person responsible for that was under tight time pressures when he wrote it.