Implementing bool() without any conditionals
Python - 122 chars - 50*13 types = -528

def b(x=False):
 try:return[False][x]
 except IndexError:return True
 except:
  try:return b(len(x))
  except:return True


Works for the following built-in types (as listed in §3.2 The standard type hierarchy)


NotImplemented
Ellipsis
int
long
bool
string
unicode
tuple
list
bytearray
set
frozenset
dict