This Instructable addresses only the actual flicker electronics. Integration into lanterns, pumpkins, candles, etc. is an exercise left to the reader. Personally, I'm using this circuit in two lanterns, a molded plastic pumpkin and for a string of pumpkin lights.
Note: There are at least two types of LED votives. This instructable will deal only with what I call type 1 devices - so-called because these were the first type I found. Type 1 LED votives have a small circuit board in them with a chip-on-board (COB) circuit and an LED. Type 2 LED votives have the circuit embedded in the LED itself, similar to a standard flashing LED. I have not yet determined a usable configuration for this type. For this instructable, you will need the type 1 COB LED votives. Unfortunately I think the only way you can determine what you have is to open them up.
Disclaimer: This circuit uses 120V A/C house current. It is quite capable of killing you if you are careless. All devices using this circuit should be housed in an insulated container (e.g. plastic). This is not recommended as a beginning electronics project. The poster disavows any responsibility for damages, injuries or death sustained as a result of constructing or using this circuit.
Hey, we all know anything really fun can kill you ;-)
Another note: This instructable is somewhat of a skeleton (hey, it IS Halloween). The author expects anyone knowledgeable enough to construct this can figure out how to put it together on something other than a breadboard.
This circuit is NOT approved by Underwriters Laboratories!