@damfino - Twinkle ?  -  absolutely nothing wrong with that....  Do you have any idea yet about just how many variations of that "simple tune" you can play and how much something so simple can bring to you ?  If not - work with this -

(1) get the tune seriously stuck in your head ( not difficult ! ) 

(2) "shuffle" it - very simply - double-bow ( up-down, or up-pause-up, down ) etc

(3) "knowing the tune" plant in little trills while playing anywhere it "takes your imagination" ( KNOW the sheet, but forget it while playing )

(4) play ANYTHING that "fits in with the tune" ( it does help if you can hear the basic melody while playing, of course )

(5 through 12) not gonna tell you about those yet ( LOLOL ) - but do a google search for the "twinkle variations"... and you will be amazed - and thanks to @Barry for pointing that out !

(13) - And - it gets worse - beyond the 12 variations - this is MINE - play it backwards (from the sheet) - there are of course two ways to do this - (a) play it backwards just as it is written, or (b) - much more difficult first few times round - play it backward but with the "normal" ( as in playing forward ) note timings....  arggggghhhh  - you will never be bored....  I couldn't manage that without scoring it on sheet -  simple as it is.... LOL

And yes - really -  I have done this and you may well ask .... why ?       Well, it is probably better not to ask..... LOL  

BillyG