Just a little exercise I found to practise major scales a little differently. Ascend in the normal way but coming down change the 2nd and root, to the corresponding degrees of the scale a semi tone above. ie C B A G F E D# C#. Continue by ascending in the new scale you have now reached and apply the same idea. Once this is completed in all keys on the descent try changing the last 3(4, 5 etc) notes to the scale chromatically above.
This was an idea i wanted to try in order to improve my fluency and flexibility of changing from one scale to another during soloing. Lets see if it works! I see there are many more possibilities to this and will post some more ideas when I find them.