And where did you hear that? There are no historical sources indicating any such practices.
Here is an excellent debunking by a pagan. There are literally tons of rubbish written about the druids, none of it going back much farther than the mid 1700s.
As I said before, I would love to see any historical source indicating that maypoles were in use before the 1500s.
Morris dancing was an English variation on Spanish and Italian court dances which were all the rage in the late medieval period. These dances were derived from Middle-Eastern dance forms involving lots of intricate legwork and kerchief-brandishing, accompanied by pipes of different sorts and darbukkas. Morris derives from Moorish.
Blackface morris was performed in some parts of the Welsh Marches but hardly extensive. There are far more obvious explanations for it than ancient pre-Christian rituals for driving out evil spirits. Consider the sort of thing that went on during holidays, lots of drinking and vandalism. You wouldn't necesarily want your boss or in-laws to realise who smashed their fence and peed on their garden.
I have an uncle who once wrote a letter to family and friends describing barbecues as ancient pagan rites. It is a wonderful example of Gravesian logic. You see, the ancient Canaanites would offer up sacrifices upon their altars during festivals. A high priest would officiate at the ritual, muttering different incantations and so on. We live within the territory of ancient Canaan, so, naturally, there must be some echoes preserved within the national consciousness. What happens at a barbecue is this. The community gathers together on a festival day. Someone is chosen to take charge of the whole affair (often hereditary). He prepares the mangal, a metal box which must be a modern survival of the ancient altar, heaping it with coals and ritually cleansing the grill with onions. Sometimes special substances are sprinkled over the coals, in hopes of a more propitous sacrifice. The officiator jealously guards his position, invoking the help of nature gods by fanning the flames with some sort of object, in hopes that they will be pacified by the smoke. He chants various things and sings.
When the time is judged right, the offering is placed on the altar.
The officiator lays claim to the best piece. The rest is divided among the community, just as in olden times. How can anyone doubt that barbecues are rooted in ancient pagan rituals? =)