I was also stuck there for a better part of the day as a result of a visa screw up when travelling to Dubai.
Had to take a morning flight there then the 3pm return to Dubai. I had the taxi chap take me to one of the two malls in Doha where I discovered that none of the restaurants served alcohol
Walking/sitting around a mall in Doha for 5 hours completely sober was one of the least enjoyable things to have happen to me on holiday.