Paying $2.10 per hour (Amazon pricing as of 16 Nov 2010) for the spec of:
22 GB of memory 33.5 EC2 Compute Units (2 x Intel Xeon X5570, quad-core "Nehalem" architecture) 2 x NVIDIA Tesla "Fermi" M2050 GPUs 1690 GB of instance storage 64-bit platform I/O Performance: Very High (10 Gigabit Ethernet) API name: cg1.4xlargeThat may not sound inexpensive in long run, but you now have the option to pay little for great fun, which is cheaper than a movie ticket. Get the systems for a few hours solving great puzzles. That sounds like an interesting weekend activity.
High Performance Computing Using Amazon EC2