I've successfully used the format found in "Logic Puzzle" magazines.
These are those puzzles that you solve on a grid of possibilities.
Usually they are things like work out which pet belongs to which person based on a list of statements.
These can be easily adapted to a fantasy or other setting and given a reason for needing to be worked out.
For example:
There's been a murder at the masked ball. There are three suspects:
Alice the Bard
Father Cuthbert the Cleric
Lunk the Stupid
They wore each a different mask:
Cat Mask
Dragon Mask
Orc Mask
They each favoured a particular drink from the bar:
Druid-tended Buckleberry Juice
Landlords Finest Mead
Elderberry wine
Now given some clues the players have to work out who wore which mask and favoured which drink. If you introduce the fact that we know which mask killed the mayor, then there's a reason to work things out to deduce who was wearing that mask.
For example
The barkeep when questioned let's the players know that the person in the cat mask
ordered the juice.
The players know that the Cleric is tee-total.
The murderer wore the Orc mask.
Given those clues we know it wasn't the Cleric that did the deed. A couple of more clues will lead us to the actual murderers identity.
It's easy to adapt the puzzles you can find online and just change the wording of the people/items and clues.
Also you could have more clues backed up to give the players, and give different amounts of experience based on the number of clues they needed to solve the puzzle.
You could integrate this into skill challenges by having skill checks to reveal the clues.
Sometimes, all that's needed to get shy, anxious players to open up is time. If they're more secure in their place in the group and in how their contributions will be received, they'll relax.
One big factor can be the group itself. If you've got a group where one or two people consistently dominate discussion and action, and a couple of others tend to hang back, try running a session or two without the more active people. The quiet ones may be both somewhat intimidated by the active ones and have learned to "lean" on them. Having to play on their own for a bit might help them build up confidence, while also forcing them to get more active and drive the game on their own. I'm running a campaign right now where the "quiet people" from the last one are my most active players, because the guy who dominated the last campaign I ran with them isn't around anymore. They're now the ones demonstrating how things work to the new people.
Nudging them to contribute more can also help, but be careful; in my experience it works better to offer them opportunities to get involved and to only directly push occasionally, and after they've had some time to warm up. Jumping on them directly at the beginning of the session will often make them freeze. This happens to me sometimes when I'm a player, and it can be very frustrating. Instead, I've had good results with mining their back story for things that will interest and engage them specifically.
Best Answer
My girlfriend and I have played 4E D&D and she is completely blind. Here are some of the things I did to help her out:
Our gaming sessions have been very fun and successful, and never did any player at the table feel like the game was slowed down in any way.