I want to record an episode of PBS' Great Performances next week which is broadcasting in the Seattle area (I will be there), but not in my home area, so this renders my Slingbox useless for this exercise. I want to minimize the cost of this process, although buying/returning hardware is an option if that's the only way.

The setup will be a Comcast HD cable box with DVR (I already know pulling the DVR recording over to the Macbook is not an option) - I can record either the live stream or replay the recording, but I basically want to capture full HD quality.

I thought of going to Bestbuy and getting another Slingbox to rebroadcast the show on my home network and at least get the video/sound on my laptop, but I don't know what software will record it from there.

If I run a coax cable from the output of the cablebox, is there a USB or Firewire TV tuner I can connect to the Macbook that will act as both a TV and DVR and deposit a playable HD quality recording of the broadcast on my laptop?

I highly doubt that the coax output of the cable box will be HD - most likely just SD analog for old TV's.

You'll need to use the component out, then record using something like this:

http://www.amazon.com/gp/product/B00...ag=prd_idnr-20

You can't use HDMI to record due to the rights management... Also, I think they most it'll do is 720P.

Alternatively, if you know anyone in the Seattle area with a TiVo, they could record it, and offload it using TiVo To Go...

Or, just download it off the Piratebay, assuming you live in a country where this is not against the law

Wow that sounds very complicated - so there is no such thing as a HD cable tuner for Mac and software that will record in real time?

I checked Piratebay (not sure if I was connecting to the correct site from my network), but there is nothing there - it's not exactly a popular file to record and upload (PBS Great Performances, Live from the Met).

Can't you just stream it off of Hulu or PBS's website?

Unfortunately Hulu doesn't carry these broadcasts and the PBS affiliate showing it next weekend does not stream live. The Met has pretty tight control over their broadcasts, so streaming or replay is unlikely. If I knew this event was headed for DVD soon, I wouldn't bother recording it - but it could be a year or more before this goes to DVD, or possibly never.

When needing to do the same thing (recording locally telecast content on the road), I take along a USB tuner and record over the air. The unit I use is also from AVerMedia and integrates into Windows Media Center...but it also happens to have drivers for the Mac and software to have your laptop act as a DVR. A nice bonus is that the recorded content is usually stored in a standard format (H.264 or MPEG) and can be moved to other platforms for viewing.

The one possible challenge with this approach is getting a decent signal, but I've found that the newest generation of portable antennas (look on Amazon, they're plentiful) provide for nice reception in places close to a city (i.e., not a distant suburb).

+1 - this is likely to be the easiest approach by far. You should be able to get a USB adapter and antenna very cheaply. Check http://tvfool.com/ using the address for where you'll be to determine the likely quality of the signal.

Looks like this could be an option, but I will probably need to drive closer to the transmitter - but I haven't been able to find a HD antenna and USB for the Mac, and I don't know which software I should use to record. I guess I can stop by Radio Shack for the antenna, but any specific suggestions would be helpful.

A quick perusal came up with the following:

Portable antenna
http://www.amazon.com/August-DTA240-...ble+tv+antenna

USB tuner
http://www.macmall.com/p/Elgato-TV-T...71~pdp.gbjfegi

Elgato's EyeTV HD should be able to do what you want...
http://www.elgato.com/eyetv/eyetv-hd