The taste and smell of many vitamin supplements can be unpleasant to some people. The culprit is usually the B vitamins. If you leave these out, the other vitamins generally are not a problem.
The vitamins available on this Web site don't smell or taste terrible to me or to most people, so you could try those. Otherwise, I'm afraid finding an odorless multivitamin/mineral is a matter of trial and error.
If you can't find an acceptable multivitamin/mineral in tablet or capsule form, you could try liquid vitamins. Although they're more expensive than vitamins in other forms, you might find them palatable when blended with juice or other drinks. In the past, I've recommended liquid vitamins only to those who have trouble swallowing pills. They're not any better for you than vitamins in tablet or capsule form (although it's a safer bet that you're getting the vitamins and minerals into your system, unlike some tablets or capsules that may not fully dissolve). Another benefit is that you may be avoiding some of the additives that pills contain to prolong their shelf life. The biggest disadvantage is that many vitamins - particularly vitamin C - begin to break down upon exposure to air, so in some cases, the potency of liquid vitamins may begin to wane once you open the bottle, or sooner if they aren't well manufactured.
I'm currently trying to develop some vitamin-infused waters for people who don't like to take pills, but haven't yet come up with the ideal formula. I'm not impressed with those on the market today. Most give you extra calories and unneeded additives. While the perfect vitamin supplement still is a concept in progress, I'm at work on the problem and will let you know when I get closer to solving it.
Andrew Weil, M.D.