Had a few similar expereinces to this.
I was on my solo Xcountry to Bismark, and center handed me off to Bismark tower, and they cleared me for a right base to final approach, i was number one with an MD 80 about 5 miles out. I confirmed and set up the approach as I was turning final, the controller called up and canceled my landing clearence and told me to continue the turn for an extended down wind (basicly to make a 270 degree turn). As I turned I glanced out my window and saw the MD 80 not more and a mile or so away and heading right for me! Full throttle and pitched to almost 50 degree of bank. He called the MD and gave him traffic, in the back ground of the call I could hear his TCAS going off, and I laughed. I made 4 more landings there and then continued on to Jamestown and back to the Forks.
On another practice flight, I was coming into Grand Forks. We have 3 runways here, two parrell (35/17) and 8/26. I was coming in from the west and was cleared to fly a left cross wind, cross 35L, for 17L. As I was crossing center line of 35L, a learjet went missed as he was touching down and started his climb out. Oh shit. Before the controller called, we were already making a right 180 back towards the west. However when he called, he said make a right 180 towards Minnisota. (which is east) We called back and laughed at the guy, as we knew what he meant, but none the less scary. Ended up just making another 270 and landed on 17R.
A few miles to our west, we have Grand Forks AFB. A squadren or two of KC135's are out there and like to do a lot of pattern work for some reason. Granted the pattern for them is huge, but its fun to watch. Anywho, im on with approach, which is actually the RAPCON at the AFB, transitioning through the AFB airspace, and KC-135's are doing touch and goes right underneath me. It waws fun, however when i went out the other side, they had me only 500' above their pattern level. So im puttin a long at a fast 90kts, and here comes this Heavy 135 right for me. Thats enough to change the color of your underwear.
And probably the coolest thing thats every happened to me here involves the Happy Hooligans. They are an F-16 squadren outta Fargo. There are a couple of MVAs up here they play in. Well im on a Xcountry and center calls me up and asks if i want to participate in an exercise. Sure I say. They tell me to maintain between 4 and 6 thousand and an approximately west heading. About 30 min later, right when im thinking they were messing with me, two f-16 rocket over the top of me, and pull straight up, and head for the sky. Amazing. Later I found out from a friend they do it quite often, center calls up the base and tells them they have a threat at this mark and they scramble the jets to intercept and destory. So i died that day, unless my warrior had some special weapons i didnt know about.