[DIY!]How to convert DC(say 5 amp,12 volts) into very high voltage (say 1000V)?

Now the input is as said before:
5 amp, 12 volts ...DC

I need the output to be like greater than 1000V ...
The output can be DC, AC,half/full rectified / pulsed....but of high voltage....

the topics im familiar with are transformers, ac generators, LC circuits, transistors, p-n junctions etc...

Now I want to do this experiment as a project for real...for school...
All I need is a way to do it, a sample circuit would be perfect, or a link to a website that show's approximately what I wanna do...(the input must be DC and output must be of high voltage..)

I know the dangers of high voltage, I will be very careful,DUH.)

*****The output current can be anything...Assume Ideal conditions,(conserve total power)...let me worry about efficiency.

*********WE CANT USE A TRANSFORMER ! IT IS FRIGGIN DC !!!

i need a way to convert it into either pulsed or AC...a short method ...is their some way to do it using
capacitors ? transistors ? inductors ?

I NEED TO CONSTRUCT THE ACTUAL CIRCUIT MYSELF !
(Oh yes I used all caps ..)