I've had alot, some nice, some not so...
One of the funniest was in my flat in Oz, which was the lower level of a house built into a hill, and originally used as a potting shed by an old couple, both long since passed away. In bed awake one night, heard two sets of footsteps behind my head coming from what was now a cupboard but originally a back door. Quickly closed my eyes like I was asleep, and as they moved around the head of the bed toward the current front door, I heard an old woman's voice say "Shh, don't wake him up!"
Another time in the same flat, she sat down next to me while I was reading - I actually felt the mattress sag under the weight! I just showed her the cover, told her the title, and she slowly went away.
I would have told you about some of the sad characters I felt and saw in an old backpackers hostel (ex-women's refuge) I stayed in for six months, but the hairs went 90 degrees on my arms just thinking about it...the best thing they could do is pull that place down.
In short though, have felt them, seen them , and heard them. Seen an old woman and her cat (it disappeared in my hand when I went to stroke it), a dog, a man who died in a fire in a restaurant I worked in, and had my half of a shared room filled with bright points of light after me and a friend helped a poor girl move on... had my hand held in a castle in Hungary, and my shoulder held firmly but kindly while extremely depressed and suicidal on one occassion - physically felt my heart and head lighten, and actually broke down in tears ! ( Anyone who knows me, knows that is NOT a part of my character!)
On one ocassion even dreamed of the encounter about 6 months before it happened, and brought a friend closer to the memory of his grandfather when it actually occurred.
The most bizarre of all though was probably when given the feeling of being a corpse on one ocassion, by one of the hangers-on at the old man's place (an old Magistrates house complete with prison, built in 1833). My whole body went frozen and hollow, like being in a vast cave, the only thing inside me my heart, and that beating loud as hell. They levitated me about 2-3 feet above the bed till I asked them why they remained, and don't they want to move on. They quickly let me back down, and I saw a source of light retreating through the closed door.
(Also heard footsteps upstairs while alone in the same house, and the sound of someone opening a courtyard gate I knew was locked, and leading a horse in in the middle of the night - of course there was no-on there when I went out to check.)
A ton more such occurrences, but won't write them all here. Usually they just like you to know they're there (feeling of cobwebs on your face, hairs rising on your neck and arms, body going numb, or strong backache if they want you to feel their pain). Important to remember though that they can't effect you if you don't let them - problematic ones need to be told short and strong that they have no place here and to move on.