I found this one while scrolling around in Kansas City. I think it looks like an octopus.

Such a list would not be complete without this one..

I-85/I-285 interchange outside Atlanta, affectionately known as Malfunction Junction.

When I left there in '83, this was a simple cloverleaf. If you got caught in the right lane during rush hour (roughly 6am until 10pm ), you could theoretically be trapped in an endless loop until you ran out of gas..

So they "fixed" it..

Since the "upgrade" it's been re-christened Spaghetti Junction.

Considering the engineering involved, it's actually quite effective in routing the ridiculous amounts of traffic that it sees.

The 'Oakland Maze' . Check out the 360 View here.

This was rebuilt after the collapse of the Cypress freeway in the 1989 Loma Prieta Earthquake. You can see the trace of the old freeway just to the south as the Mandela Parkway. Previously the neighborhood to the west of the Mandela Parkway was cut off from the core of Oakland and had evolved into a kind of no-mans land. When the freeway was rebuilt, it was routed around to the west to rejoin the neighborhoods. history
more history

We also have this one in Louisville called The Spaghetti Junction.Interstates 71, 64 and 65 all cross here.

It is going to cost $786million to rebuild and expected to take 13 years.

Here's a folder of some Houston interchanges. What makes some of these challanging is not the interchanges, but their close proximity to each other. It can be a real bioch trying to get over in the right lane, especially during rush hour.

EDIT: Added 3 more just 'cuz they're nice to look at.

Of course we couldn't forget LA. These are just the 5 major interchanges surrounding downtown Los Angeles, all within a very short distance of each other. Better know where you're going before you get here. Signage and heavy traffic most hours of the day make things even more interesting. Speaking of signage, here's an interesting link.



Hill

You wouldn't know it, but this interchange ends up looping around onto of itself.



the Queensboro bridge, a beautiful double decked bridge hoists two levels of traffic over the East River. The trick is getting traffic into two levels in a limited amount of space. In addition a previous subway track has been replaced with a Rush hour roadway, which doubles as a Bikeway.

The original plain and what the decks do now:

Here is a picture of part of the interchange as it goes under the 7 and the NW of the NYC subway and as it approaches streets

The list should also include the interchange of the Garden Grove Freeway (CA-22), Orange Freeway (CA-57), and I-5. It's very easy to end up going the wrong way here.

This, according to the NHSTA, is the most congested freeway interchange in the States. Approximately 27,000,000 man hours of work are lost by commuters waiting in traffic where the 405 and the 101 freeways merge here in Irvine, CA.