It might help if you would describe exactly what you're using them for, or no one can help you.. Your description so far explains pretty much nothing. Charged and discharged are relative terms, they can be any arbitrary voltage level. LED relay etc.. describes every electronics device known to mankind, again no help because nothing will meet the demands of every application.
Would you care to actually supply some information that we can work with? Flip flop style timer is a misnomer, as a flip flop can't time anything even if some timers use flipflops.
My post was pretty well detailed, but I'll break it down a little further in case I wasn't clear.
Charged and discharged are not relative terms. A capacitor will draw energy from a power source until the voltage potential between the two sides of the cap is equal to that of the power source, at which time the current drawn by the cap is 0 and stored energy is at maximum. The capacitor is said to be in a "charged" state. When the two leads of a capacitor are connected, current will flow from the negative side of the capacitor to the positive side until the balance of charge between the two sides of the capacitor is restored. Then, there is no more stored energy in the capacitor and it is said to be "discharged."
If you connect a device which operates on electric energy between the two leads of a "charged" capacitor, the device will be able to operate off that energy until the capacitor has become "discharged."
The device I intend to make will charge a capacitor and then discharge it through a device (again, could be a LED, relay or anything within reason). My mistake was calling it a timer, because it is not. The time it takes to charge the capacitor will be used as a delay, which I can alter using a resistor. The device will operate for as long as it takes the capacitor to discharge through it, another variable determined by my selection of components. In the end, I'll have a device which operates every X seconds for Y milliseconds.
I don't intend on working with exotic materials, so you can safely assume I'm looking to build something that works off a battery. I can tweak the values of components to suit my purpose, so you need not worry about providing exact Farad, Volt, Ohm, etc values, I am just looking for a starting point, a basic circuit layout, something to that effect. I'm not like the hundreds of kids you probably have come through the forums who want you to design it, simulate it, build it, perfect it and then mail it to them. I just want some experienced help doing it myself.