The trouble with most religious observances, it seems to me, is that they're not distinctive or outrageous enough. Some of them, it turns out, might actually make sense! That's no good. I mean, sure, we live in a fast-paced world and all that, but that doesn't mean we can afford to have our rituals and superstitions be practical - where's the faith in that? How are you going to prove that you're a true believer if the actions you take to demonstrate this to people aren't at least somewhat wrong-headed and inconvenient. You might as well claim that checking mail is an act of pious devotion.
Take this whole vegetarianism thing. Say you see someone eating a soy burger at a fast food joint. It could be that he's Hindu or Buddhist or something and doesn't eat meat. Or it could be that he's a heart patient, or on a diet. Or it could be that he's just read a lot of Shelley. Or maybe he had his taste buds shot off in Iraq and now actually likes soy. Or perhaps he's just from California. The point is you can't really tell, can you, so that if you are a Hindu there's basically no point in giving up steak because no one's going to think it noble of you anyway.
The whole point of all this religion mumbo-jumbo, after all, is that a) it sets you apart from everyone else and lets you turn up their nose at them and call them things like infidel behind their back (or, if you're a bona fide Ayatollah, to their face) b) it gives you an excuse to pick fights with total strangers and c) it gives you the opportunity to act morally affronted at regular intervals thus making everyone around you feel bad about themselves and putting them on a guilt trip that you can use to get things out of them later.
It follows that to make a good taboo work, you need to pick something that's commonly used, entirely unobjectionable but not too inconvenient to do without (you don't want, for example, to go around making essentials like fire or clothing or cappucinos taboo). Something like blow-dryers, say. Or forks. Picture yourself calling the waitress over in a restaurant, fixing her with a mournful stare, and informing her in a wounded voice that there are four forks on this table and you, as a devout Falstaffist consider forks to be the embodiment of Lucifer and so would she be so kind to remove them, and oh, could she also get you a new glass because your fork was touching this one. Or jumping out of your seat when the hairdresser starts blow-drying your hair, and grabbing a hairbrush and holding it in front of her crying "Get thee behind me, Satan!". Those are the kind of religions we need more off. Not the kind who go around slamming airliners into buildings, but the kind who consider ringing cell-phones blasphemous or believe fervently that to talk about your child at any point before he / she is 18 years old is to call down the blistering wrath of the Gods on his / her head.
Oh, and special days - how could I forget those. If you really want to grab attention, what you need is a religion where the 25th of December marks the death anniversary of your greatest prophet and is therefore a day of silence and mourning. Think what fun that would be. You could walk / drive around the city wearing black and looking glum, depressing the hell out of everyone else. If someone said Merry Christmas to you, you could turn around in shock and burst into tears and cry "How could you? How can you be so cold, so heartless? Don't you know our Great Panjandrum died today?" You'd be in all the papers. Civil rights groups all over the country would take up your cause and argue that being happy on Christmas was a sign of ethnic bias. Any office that put up a Happy Holidays poster in a public area would be considered a hostile work place.
If you really wanted to take this argument to its logical extreme you could decide to make a colour taboo. Say blue. That way you could object to the sky, argue that it offends you, refuse to leave your home on days when it's clear. If the people you work for try to fire you because you only get in to work maybe once in eight days (obviously this won't work with UK weather) you could accuse them of discriminating against you because of your religious beliefs and either keep your job despite doing nothing or get paid hefty damages.
And then people say that religion isn't relevant in our times.