I have a house built in the '50s, and the wiring is all 2-Wire (no ground). My understanding is that surge protectors will not work without a ground.

How can I obtain surge protection for computers/televisions/etc?

That is my understanding of varistor and gas plasma based ones too. Two alternatives. I just installed a GE surge Pro THQL in my main breaker box. Even your 50's house has the neutral grounded at the main panel. It should knock incoming surges down to 600 volts. You need to fit your box with its same brand of whole house surge protector.

See Surge Protectors, Surge Protector Manufacturers - Brick Wall (http://www.brickwall.com). While lightening is DC, it is high frequency pulsed DC. The proper inductor passes 60 hertz AC like some much more 12-2 NM, but provides very high resistance to high frequency pulsed DC. This is something I have read about on the net. I have not had a lightening strike hit a Brickwall protected line.

If you house is wired up with properly installed BX or metallic conduit, it should provide the equipment ground you need. If so a quick check with an ohm meter will show you have a low resistance between the neutral and the screw holding the outlet cover on. You could run a ground to a water pipe or something, but I understand that violates code.

After thought, a varistor across the hot and neutral even ungrounded provides some protection.