I always try to make it to at least one of the local Christmas light up festivals on Vancouver Island. This year happened to be the Ladysmith Festival of Lights which is always spectacular with over 200,000 lights being turned on in the historic downtown core by Santa Clause.
From a photography standpoint it must be one of the hardest shoots I do every year. Until the lights are lit there is virtually no light to shoot with. I generally have to push my ISO up to at least 1,600 or more and still have shutter speeds down in the 1/10th range at times. A typical exposure seems to be about 1/25th at f1.4, at least I have a 30mm 1.4 lens available. Once the lights are on it improves a little and during the parade I shoot with my 17-55mm f2.8 lens for a little more flexibility. Even then, shutter speeds around 1/20th or so are normal and with moving subjects keeper percentages are low. Shoot lots and hope for the best!
The fireworks are the easy part! Camera on a tripod, ISO 200 and f8 or f11 with the shutter set on bulb. One to 5 seconds seems to provide good exposures.