BlueCurve is a theme, similar to skins in XMMS/WinAmp or Mozilla/Netscape or themes in MicrosoftWindows (9x/ME/XP). It was unique for its time, in that it included GNOME, KDE, Metacity, GTK+, and XMMS parts. It also included an icon theme, using RedHat-designed icons. It was developed by RedHat and introduced as the look&feel of RedHatLinux in versions 8 and higher.
In a way, this is the first step to removing the GnomeVsKde problem. There's two big choices out there and an application for one would look really really bad when being run on the other.
"It's an effort to unify the look and feel," said Erik Troan, Red Hat's director of product marketing. "Users shouldn't have to worry about which (interface) to choose," and programs should work the same on either GNOME or KDE. "We're not trying to create a 'third user interface,'" Troan says. Instead, the theme is aimed at "a consistent look and feel [which is] 'polished' and more '3D.'" "We didn't want to use just GNOME and get KDE users upset. We didn't want to use just KDE and get GNOME users upset. Instead, we combined the two, and got everyone upset," he quipped.
You can see some good screenshots:
If you use Gentoo, you can type emerge redhat-artwork and get the BlueCurve theme.