I found that Mason jars work well. Pour in some liquor and then add the stuff you want to infuse, screw the lid on and let it go for an hour or so at 170 degrees or so. Sometimes I will pull it after 30 minutes or so and give it a good stir and then put it back in. When it is done, pour it through a strainer into another Mason jar. I then just keep the newly infused liquor in that Mason jar and store it in the fridge. If you do some googling you can find some pretty interesting recipes/ideas for sous vide infused drinks.
Some ingredients that I have found that work well are mint (especially for simple syrup) and real vanilla bean. I also found a recipe on-line to make homemade Grand Marnier (brandy, sugar, and orange and tangerine peels).
Edit to add that I probably actually did it at less than 170 degrees - maybe more like 150 to 160? I usually look it up on-line before I go at it. Perhaps I should start making some notes, so I don't half to reinvent the wheel each time.