Jaguars are trailing by a touchdown, no timeouts left, and they complete a pass to the Colts 12 yard line with exactly 1 minute on the clock. To me, time is not an issue at this point. But the Jags spike the ball, making it second down. Stupid move, because now you only get three shots at the end zone instead of four.
Of course, as I type this, Garrard throws one out of the back of the end zone and then gets sacks to end the game, confirming that the Jags suck. In general, there's almost never a reason to spike the ball, except for stopping the clock to allow your kicker to come on to the field. If you're running your offense, then run a play, because you have to get everyone back to the line and set anyway.