Chop the fried bacon into bits and set aside. Saute the garlic in a tablespoon or two of the bacon fat (or use olive oil). Chop the arugula into 1-inch pieces, then add to the garlic and saute until just wilted (about 2 minutes). Add the cream and stir to heat, then stir in the bacon. Meanwhile, in a large pot of boiling water, cook the pasta until just tender. Spoon the sauce over the fettucine and serve hot, with grated cheese.