Stellar Conquest
Truly a classic game, the grandfather of empire-building that's brought us to computer games like Masters of Orion and Starcraft. This boardgame for an evening with two to four players is also subject to some upgrading - I've got some alternate rules developed by myself and others over the years, play-*test*-('")ers are invited !

Rules upgrade
some really vital fixes (IMHO) #1 Death Stars/Battle Spheres/Dreadnoughts, the largest units - whatever you call them - should always move 1 slower than your current maximum. A reason to keep building smaller units. #2 Population transfers between planets in the same starsystem shouldn't recieve the Emigration Bonus - there's no time to breed extra colonists on a simple interplanetary trip.

Variant rule
I think another enhancement to keeping smaller ships in play throughout the game comes from this Variant on Scouting a System. The Hazards roll is applicable to all Scouts without at least one military ship escorting, and to a force of four or fewer Corvettes without at least one Scout ... the larger combat ships aren't at risk from mere random/natural hazards. In games over the years we had tried out but never settled on a version of this rule that spotlighted Colonists also - debated whether they would be a help or a hinderance - clumsy, disorderly, greedy blighters who would increase the chance of running into a plague or being caught by a solar flare ... or a valuable resource in overcoming challenges (one million ought to include at least one Wesley Crusher). One suggestion was first-time explorers including Colony Transports have them check first and if any fall victim, then the roll for the scouts/military is worsened to a 5 or 6, what do you think ?