There's a few trails around Sassafras that are pretty fun to cruise around, mostly fire-trails and no real singletrack, but still makes for an OK ride.  If you combine it with a climb up from The Basin or Ferntree Gully then you can have a workout as well.  Basically there's a network of fire trails between Mountain Hwy (Mtn Hwy) to the north, the Tourist road to the south, the One Tree Hill picnic ground to the west and Hilton Road to the east.  Most of the trails are in the Melways.  I do the following loop regularly.

Turn off the Tourist Rd onto Hilton Rd, and follow it all the way to the end, go around the gate and you'll be facing a steep descent on a rocky firetrail.  About 150m down you come to an intersection.  Turn right and you'll eventually come out on Mtn Hwy, straight ahead is the continuation of Hilton Rd and also leads to Mt Hwy, and to the left is Helen track.  Turn left onto Helen and you get a great fast undulating fire trail.  Follow it until you hit a dead end, and you'll see a trail veering off to the right heading downhill.  Take this trail, and watch out, it's quite steep and rocky but good fun.  At the bottom turn left and follow this trail until you come to a fork.  The left road heads slightly uphill, the right goes downhill.  Take the trail to the right and again there's some great undulating fast trail that you can really fly down.  Follow this all the way down until it looks like you're riding into someone's back yard.  It's OK I've ridden here heaps and never seen anyone.  As you near the bottom you'll see that The trail basically hits Ferndale rd where it crosses Mtn Hwy, but as you near the main road you'll see a gate, and a trail heading back up the hill.  Turn sharp left and go up this trail (which is Ferndale rd).  This is the nadir of the run, so what goes down must go up.  The climb takes you up averagely inclined fire-trails, with some steep and some flat sections.  Eventually you'll come to a big clearing,  there's some new trails being bulldozed off to the right, don't go down these but follow hte main trail which arcs gradually up to the left.  This is a long slow ascent, and when you get to the top of this section turn right, and you get some repreive as the trail flattens out.  As you go through a grassy area look ahead and you'll see a steep section coming up.  I personally have never made it all the way up this section without having to walk the last 10-15 metres, so change to granny gear and spin your legs off and see how far you get.  When you get to the gate go straight ahead along the gravel road which winds around until it hits One Tree Hill road.  Turn left here and there's a bit more of a climb on the paved road before you get a cracking downhill run back to the Tourist Rd.  You come out right near Sherbrooke Rd, and only a short distance from Hilton Rd where you started.  From here you can continue up to Olinda, coast back down the Tourist Rd to Ferntree Gully or go for a walk in Sherbrooke Park, or coast down to Kallista for a cup of coffee and a banana from the organic grocer.  The choices are endless!

There are a few variations to this ride that you can figure out with a map and some time.  I suggest that you buy a good map  (you can by the "Dandenong Ranges Activities Map" by Feathertop Maps at the Aussie Disposals at Knox shopping centre - it's the best map of the Dandenongs tracks, cost $8.95) and do some exploring.  Unfortunately there's no real singletrack in this part of the Dandenongs but the fire trails are still fun.

 Pros:

    * Flowing firetrails that you can get some good speed on

    * Easy to follow loop that takes about an hour to complete (depending on your climbing skills)

    * If you think you're lost all of the trails that head downhill eventually come out on Mtn Hwy, which if you follow it back up the hill will take you back to Sassafras  

Cons

    * No singletrack!

    * Some may find the climb back up annoying, but it's nowhere near as bad as the climb out from the Black Hole!   

    * A firebug was lighting fires in this area in Jan/Feb '07! Bastard! 

Suggested Equipment

As it's a relatively short ride (around an hour) one water bottle is usually enough, on hot days you may need more.

Gels/energy drink/lollies - may give you a boost on the climb

The usual: water/camel-bak/spares/clothing/helmet/lights etc!

Mobile Phone - to report fires in summer.  If you crash it's not too far to walk out to a main road/civilisation (there's houses around you can go to if desperate), but a phone is always handy.  The coverage is slightly better than elsewhere in the hills, still Telstra or 3 have best reception.