diff --git a/src/calibre/__init__.py b/src/calibre/__init__.py
index 4150b4b339..8e1b32b03d 100644
--- a/src/calibre/__init__.py
+++ b/src/calibre/__init__.py
@@ -170,8 +170,8 @@ def prints(*args, **kwargs):
         except:
             file.write(repr(arg))
         if i != len(args)-1:
-            file.write(sep)
-    file.write(end)
+            file.write(bytes(sep))
+    file.write(bytes(end))
 
 class CommandLineError(Exception):
     pass
@@ -278,12 +278,18 @@ def get_parsed_proxy(typ='http', debug=True):
 
 def random_user_agent():
     choices = [
-        'Mozilla/5.0 (Windows; U; Windows NT 6.0; en-US; rv:1.9.2.11) Gecko/20101012 Firefox/3.6.11'
-        'Mozilla/4.0 (compatible; MSIE 6.0; Windows NT 5.1)'
-        'Mozilla/4.0 (compatible; MSIE 7.0; Windows NT 6.0)'
-        'Mozilla/4.0 (compatible; MSIE 8.0; Windows NT 6.1)'
-        'Mozilla/5.0 (Windows; U; Windows NT 5.1; en-US) AppleWebKit/525.19 (KHTML, like Gecko) Chrome/0.2.153.1 Safari/525.19'
-        'Mozilla/5.0 (Windows; U; Windows NT 6.0; en-US; rv:1.9.2.11) Gecko/20101012 Firefox/3.6.11'
+        'Mozilla/5.0 (Windows; U; Windows NT 5.1; en-US) AppleWebKit/523.15 (KHTML, like Gecko, Safari/419.3) Arora/0.3 (Change: 287 c9dfb30)',
+        'Mozilla/5.0 (Windows; U; Windows NT 6.0; en-US; rv:1.9.2.11) Gecko/20101012 Firefox/3.6.11',
+        'Mozilla/4.0 (compatible; MSIE 6.0; Windows NT 5.1)',
+        'Mozilla/4.0 (compatible; MSIE 7.0; Windows NT 6.0)',
+        'Mozilla/4.0 (compatible; MSIE 8.0; Windows NT 6.1)',
+        'Mozilla/5.0 (Windows; U; Windows NT 5.1; en-US) AppleWebKit/525.19 (KHTML, like Gecko) Chrome/0.2.153.1 Safari/525.19',
+        'Mozilla/5.0 (Windows; U; Windows NT 6.0; en-US; rv:1.9.2.11) Gecko/20101012 Firefox/3.6.11',
+        'Mozilla/4.0 (compatible; MSIE 6.0; Windows NT 5.1; .NET CLR 1.1.4322; FDM)',
+        'Mozilla/5.0 (Macintosh; U; Intel Mac OS X; en; rv:1.8.1.14) Gecko/20080409 Camino/1.6 (like Firefox/2.0.0.14)',
+        'Mozilla/5.0 (Macintosh; U; Intel Mac OS X; en-US; rv:1.8.0.1) Gecko/20060118 Camino/1.0b2+',
+        'Mozilla/5.0 (Windows; U; Windows NT 5.1; en-US) AppleWebKit/534.3 (KHTML, like Gecko) Chrome/6.0.472.63 Safari/534.3',
+        'Mozilla/5.0 (Windows; U; Windows NT 6.1; en-US) AppleWebKit/532.5 (KHTML, like Gecko) Chrome/4.0.249.78 Safari/532.5',
     ]
     return choices[random.randint(0, len(choices)-1)]
 
diff --git a/src/calibre/ebooks/metadata/covers.py b/src/calibre/ebooks/metadata/covers.py
index 49e4cb1d58..10acff4e61 100644
--- a/src/calibre/ebooks/metadata/covers.py
+++ b/src/calibre/ebooks/metadata/covers.py
@@ -302,4 +302,16 @@ def test(isbns): # {{{
 
 if __name__ == '__main__':
     isbns = sys.argv[1:] + ['9781591025412', '9780307272119']
-    test(isbns)
+    #test(isbns)
+
+    from calibre.ebooks.metadata import MetaInformation
+    oc = OpenLibraryCovers(None)
+    for isbn in isbns:
+        mi = MetaInformation('xx', ['yy'])
+        mi.isbn = isbn
+        rq = Queue()
+        oc.get_covers(mi, rq, Event())
+        result = rq.get_nowait()
+        if not result[0]:
+            print 'Failed for ISBN:', isbn
+            print result
diff --git a/src/calibre/ebooks/metadata/library_thing.py b/src/calibre/ebooks/metadata/library_thing.py
index be0cd5f324..ddd4b64f58 100644
--- a/src/calibre/ebooks/metadata/library_thing.py
+++ b/src/calibre/ebooks/metadata/library_thing.py
@@ -4,34 +4,23 @@ __copyright__ = '2008, Kovid Goyal <kovid at kovidgoyal.net>'
 Fetch cover from LibraryThing.com based on ISBN number.
 '''
 
-import sys, re, random
+import sys, re
 
 from lxml import html
 import mechanize
 
-from calibre import browser, prints
+from calibre import browser, prints, random_user_agent
 from calibre.utils.config import OptionParser
 from calibre.ebooks.chardet import strip_encoding_declarations
 
 OPENLIBRARY = 'http://covers.openlibrary.org/b/isbn/%s-L.jpg?default=false'
 
-def get_ua():
-    choices = [
-        'Mozilla/5.0 (Windows; U; Windows NT 6.0; en-US; rv:1.9.2.11) Gecko/20101012 Firefox/3.6.11'
-        'Mozilla/4.0 (compatible; MSIE 6.0; Windows NT 5.1)'
-        'Mozilla/4.0 (compatible; MSIE 7.0; Windows NT 6.0)'
-        'Mozilla/4.0 (compatible; MSIE 8.0; Windows NT 6.1)'
-        'Mozilla/5.0 (iPhone; U; CPU iPhone OS 3_0 like Mac OS X; en-us) AppleWebKit/528.18 (KHTML, like Gecko) Version/4.0 Mobile/7A341 Safari/528.16'
-        'Mozilla/5.0 (Windows; U; Windows NT 5.1; en-US) AppleWebKit/525.19 (KHTML, like Gecko) Chrome/0.2.153.1 Safari/525.19'
-        'Mozilla/5.0 (Windows; U; Windows NT 6.0; en-US; rv:1.9.2.11) Gecko/20101012 Firefox/3.6.11'
-    ]
-    return choices[random.randint(0, len(choices)-1)]
 
 _lt_br = None
 def get_browser():
     global _lt_br
     if _lt_br is None:
-        _lt_br = browser(user_agent=get_ua())
+        _lt_br = browser(user_agent=random_user_agent())
     return _lt_br.clone_browser()
 
 class HeadRequest(mechanize.Request):