Many people have reacted somewhat negatively to this question. I would, instead look upon it as an opportunity.
Nearly the only reasonable excuse for counting lines of code is that it's been demanded by somebody higher up the food chain (who's clearly clueless, or he wouldn't ask for that). As such, you should get that person involved -- preferably doing something like heading a committee (that includes as many of the least useful of your co-workers as possible) researching the most efficacious way(s) to count lines of code.
As far as the specific method itself, such momentous decisions obviously require the input of the entire committee. Your job is to supply them with plenty of raw data, measuring lines of code every which way you can (at least without expending any more than a minimum of effort). You should, however, meter the rate at which you supply them with this information -- if, heaven forbid, they get close to a final decision, you need to give them an exciting new option that forces them to go back to the drawing board to spend at least a few more months studying the problem and considering how best to incorporate this new option into a company-wide line-counting strategy!
This has two good effects. First of all, it obviously distracts them from other things that are likely to be more harmful to productivity. Second, you can bolster their self esteem by supplying them with at least a little data that they will eventually realize is even more worthless than the rest, so when they write their three-volume guideline on the proper ways to count lines of code, they can make some good, solid recommendations about at least a few things to avoid, so at the end of it all they can really know they've accomplished something useful. In addition, they will have shown you mere peons that without their brilliant, seasoned leadership, you'd be making all sorts of foolish mistakes in this most crucial of tasks.
Lest you should mistake this for being entirely facetious, I'll point out that this really is quite important -- without something like this to occupy their time, they'll start to study something like ISO 9001 conformance. The minute they decide to go ahead with something like that, you might as well write off at least a solid month that will be dedicated to writing up detailed documentation of how you do your job (which, to give you any hope of passing an inspection, will end with something like: "and if none of that works, we will exercise our judgement and do what seems reasonable.") With a little care in its application, a small investment in line counting software can prevent, or least delay, such disasters for a considerable time.