I've just finished some birthday invitations for a 21st birthday. I was asked for fractals in blue, green and purple – but since I don't have a clue how to use fractal programmes, I simulated the effect with a combination of Photoshop and Illustrator. Fortunately, seahorse tail fractals were the type of choice anyway!
I created the shape to be used for the fractals in Illustrator, then took it into Photoshop, duplicated, resized and slightly rotated it, and then repeated that command until I had a swirl. It took me a few goes to get a swirl I was happy with, duplicated it a few times, and I ended up with this:
Naturally I couldn't leave it looking like that, so I added some spirograph-type designs (created in Illustrator) and some glowy bits, until I had something much more atmospheric. I added the text in inDesign, using Takion for the font; the birthday boy loves science and mathematics, and I felt that font fitted that theme nicely.
The majority of the invitations were emailed out, but for those that were to be posted, I got 5x7" prints done at a Kodak Photobooth. This meant some of the border was chopped off, but they still came out very nicely.
Photoshop, Illustrator and InDesign CS6