I need ideas for running an exterior outlet

could you not drill through a knockout in the back of an interior outlet, through the block and mount a raintight box on the exterior?

Just a suggestion. If you have a light outside by your front door, you can convert it to an outlet by putting in one of those "screw-in outlets". Now you can plug in your Christmas lights and control it with the switch inside your house. Or better yet, by a timer to replace the switch so you can control what time it comes on and off.

- The house is concrete block so making holes is not an option.

Not true. It's done all the time. A carbide tip drill bit and Tap-Con or Pro-Con screws are made for mounting things to concrete and concrete block.

In addition, a length of wire hanger, filed to a point and mounted in a drill, will allow you drill from inside the house, through the block and make it easy to locate the hole on the outside. By locating the small hole from the hanger, you can enlarge the hole by drill into the block from the outside (and inside) to avoid the blow-out that would occur if you tried to drill a large hole from only 1 direction.

Now, run the wires inside the house and though the block wall to an exterior, weathertight box.

I suggest a new circuit, maybe with a dedicated switch so Sergeant Christmas can turn her lights on and off as desired. Of course, a timer is also an option.

P.S. I've used the wire hanger trick to accurately place exterior fixtures by drilling through interior finishes, interior insulation, the sill plate, exterior insulation, and the vinyl siding. Drill though the wall, unchuck the hanger, leaving it in the hole and go around to the other side to locate your hole. Now you can neatly enlarge it from both directions. The AC guys used the same trick to drill through the block foundation to run the AC pipes.

If possible run wires from a new circuit inside the house to a spot

Don't forget about the maximum current that socket allows.

If you have an attic with an accessible soffit, putting the outlet up high will be easiest. Adding a dedicated circuit is best, but if that is too complicated, a common trick is to hang it off the bathroom circuit downstream of the GFCI outlet. You definitely want a GFCI protected outlet or circuit.

aem sends....

Good point Mark. The fixture wire in that lamp holder is 18 ga.

BTW if your AHJ uses the NEC there is an exception that allows a 120v

By current code, it's illegal to hang anything off of a bathroom outlet, except another bathroom outlet

With modern LED or neon lights, 500 bulbs will draw about 1/2 amp.

Sink a piece of treated 4x4 and attach the box to that.

Last year, I replaced a lot of my holiday lights with LED ones, and probably used less than half the electricity. Also, the colors look a lot better with LED lights.

I avoided needing the automatic exclusion switch (the year before, a lot of those lights were on the same circuit as the microwave. Trying to use both at once would trip the breaker.).

and it could be confusing when someone else moves in there, and can't figure out why the outside outlet is dead.

Chuckle. That is for damn sure. I didn't figure it out on this place until AFTER I had changed out the outside outlet, which needed changing anyway. I did not realize code had changed on this, since the 1978 addition here was built. When I asked the guys at work about it, they all indicated that their houses (all 1970s/80s vintage) were set up the same way. From previous threads on here, I think it was a rather common practice.

When I hit the lotto and build my dream house, the outside lights and power will have their own circuits, with suitable protection. And not that I do the Xmas light thing, but I will either install outlets in the appropriate places with a dedicated switch bank inside, or maybe just build the holiday lights into the roof overhang. Holiday comes, just turn them on.

aem sends....

A real man would have said, "This is my house and we don't need Christmas lights. Case closed."

Hmmmm. I like this idea. I might have to determine if the wire size can handle a larger breaker.