"Probably if you just buy some wool there that you like you can just tell everyone when you get home that it's genuine Aran wool....
Oo - you're a bad lass,
OK - I'll try and keep this short and sweet:
You're right, there is traditional Aran wool which usually comes in cream or off white, the colour used by 'Aran' knitters.
These days, you can still buy Aran wool - of the same sort of texture but in a rainbow of colours. You don't need to stick with cream or offwhite if you don't want to. You are still using Aran wool, even if it's a different colour.
Weight - Aran weight is closest to US Light Worsted.
Patterns - There's a huge variety of traditional Aran patterns and what they all have in common is, of course, using Aran weight wool.
Alot of them are quite complex and you really need to concentrate on each and every row of the pattern, especially with twists and diamonds.
The pic below is a cardi I knitted for my grand daughter - it took me forever but I learned such alot about stitch patterns, cables, twists, etc., that it really was brilliant for advancing my knitting skills.
There are, however, lots of simpler patterns, just involving a couple of cables, which I did before I bit off with this particular pattern.
Take a look on ebay UK and you will find tons of 'Aran' patterns, meaning both the traditional pattern stitches and using 'Aran' weight.
Anyway, I hope you have a lovely holiday (send me a postcard!) and hope this helps.