Every Sunday I cook up a kg of pasta and roasted veg each. You can then add your leftovers to this mixture the following day and voila - you've got a choice of pasta salad or reheated pasta in the microwave. Also really healthy and filling. You can spice it up with chillis, add fresh herbs, add a pesto, chuck in some ham and cheese if you want, stir in a sauce, chuck in fresh roma/cherry tomatoes, basil, tuna and mayo for a nice salad etc. You've got the base sorted and that's the longest part...