I love me some Classic Traveller. The books as written have everything you need to get off to a rousing start. They have mini games within games. They have rules for world building. They have funky power rules. They have a task system ... Oh wait.
Perhaps the biggest gripe about CT is the lack of a task system (if you disregard the crap about fuel use, computer size, and what tech level your favorite gadget appears). I went through the rules to resolve skills and found them a joyous hodgepodge of different rolls for different tasks with very little explanation on the justification for this target or that mod. But the basics of a skill system are there and we can't really fault GDW. Coming up with really comprehensive rules for tasks would have probably taken a fourth book and bigger box. In any case the game holds up better after forty years than most presidential administrations.
Actually CT does have a task system hidden in the skill write ups. You just have to roll up your sleeves and do a little work. Did you expect anything else? If you did you probably should turn back now.
All the rolls in CT break down to a couple of criteria. These form the dials you set for your desired task. The first criteria, the one that really catches the eye is the target number. Most of the time we're talking 8+ although 6+ and 10+ are also popular and refer to easy and difficult tasks respectively. They could also represent things like taking more or less time for a task (cautious or hasty tasks in later systems).
The next and crucial dial regards skills. I like most people always equated one skill level to +1 but this isn't really the case. A skill could give a +1 or +2 per level if it was being used in a fairly typical manner, making minor differences in skills a big deal if you desire. A situation with many external variables out of the person's control or knowledge might warrant halving the skill modifier. As an example I probably have Driver-1 just from living in New York City. I try to drive my car around a sanitation truck that affords me the three inch clearance required by the driver's sense of sportsmanship. If it was a task I'd set the difficulty level at 8+. My skill level would count as a +2 modifier (I succeed on a 6+.) Finally I take my blessed time doing the maneuver to drop the target from 6+ to 4+.
The final criteria is unskilled modifiers and anything else you can think of. Some people will would modify a task according to a stat. We modify gun combat according to DEX and melee according to STR. I DIDN'T in the example above because speed and reaction time weren't factors. I could certainly see using physical stats to modify rolls for combat or emergency situations. For example if I blew my roll to get around the truck another skill roll modified by Dexterity might keep me from tearing off my bumper.
A task should address whether it is okay for unskilled attempts and any modifiers for them. Gun combat has a -5 for unskilled use and I think this should be a maximum for life or death situations. In my driving example unskilled attempts would be fine with a -1 or-2 because everyone knows something about driving. Unskilled attempts at surgery should be avoided.
Some referees and designers feel that stats should have bearing on every task but I'm not one of those. It feels too much like skill bloat. Stats already have a huge bearing on combat. I usually relegate stats to hard and fast quantities. Dexterity gives initiative. The three physical stats give carrying capacity and so on. More on this in a later post. You're certainly free to include stat based modifiers.
I've deliberately avoided giving too many examples of tasks. This is a blog and not a game supplement and you have to decide how to set tasks to reflect the sort of campaign you want to run. Work up a few your own secure in the knowledge your players will think you're hosing them no matter what.