Ever hear of blue stragglers?
Interesting class of stars that seem to be staying on the mainstream
sequence far longer than they are supposed to:
http://www.coseti.org/lemarch1.htm
FIGURE 2: Concept of an "artificial" blue straggler star according to Reeves (1985). In this figure, a series of hydrogen bombs or powerful laser beams are aimed at the surface of a star, creating a "hot point" and rejuvenating the unused hydrogen, thus keeping the star on the Main Sequence for a longer period of time than would be natural.
Yeah, yeah, there are all sorts of normal, boring conventional answers
as to what blue stragglers are - but what fun is that?