Fairly simple to reproduce, open this page in the steam overlay.

Processor Information:
    Vendor:  AuthenticAMD
    Speed: 3600 Mhz
    8 logical processors
    8 physical processors
    HyperThreading:  Unsupported
    FCMOV:  Supported
    SSE2:  Supported
    SSE3:  Supported
    SSSE3:  Supported
    SSE4a:  Supported
    SSE41:  Supported
    SSE42:  Supported

Network Information:
    Network Speed:  

Operating System Version:
    "Gentoo Base System release 2.1" (64 bit)
    Kernel Name:  Linux
    Kernel Version:  3.6.11-gentoo
    X Server vendor:  The X.Org Foundation
    X Server release:  11301000

Video Card:
    Driver:  NVIDIA Corporation GeForce GTX 460/PCIe/SSE2

    Driver Version:  4.3.0 NVIDIA 313.18
    Desktop Color Depth: 24 bits per pixel
    Monitor Refresh Rate: 60 Hz
    VendorID:  0x10de
    DeviceID:  0xe22
    Number of Monitors:  2
    Number of Video Cards Not Detected
    Primary Display Resolution:  1920 x 1080
    Desktop Resolution: 3840 x 1080
    Primary Display Size: 20.04" x 11.26"  (22.95" diag)
                                            50.9cm x 28.6cm  (58.3cm diag)
    Primary Bus: PCI Express 16x
    Primary VRAM: 1024 MB
    Supported MSAA Modes:  2x 4x 8x 16x 

Sound card:
    Audio device: Loopback Mixer

Memory:
    RAM:  16035 Mb

Miscellaneous:
    UI Language:  English
    LANG:  en_US.UTF-8
    Microphone:  Not set
    Total Hard Disk Space Available:  905512 Mb
    Largest Free Hard Disk Block:  52997 Mb

Installed software:

Recent Failure Reports:
    Wed Jan 30 16:45:50 2013 GMT: file ''/tmp/dumps/assert_20130130114548_1.dmp'', upload yes: ''CrashID=bp-51e40c97-40a0-4f10-951a-936612130130''
    Thu Jan 31 21:13:45 2013 GMT: file ''/tmp/dumps/crash_20130131161344_1.dmp'', upload yes: ''CrashID=bp-4bad6f01-db95-41b0-b6a6-c2aa32130131''
    Sun Feb  3 02:18:08 2013 GMT: file ''/tmp/dumps/crash_20130202211806_1.dmp'', upload yes: ''CrashID=bp-5606dcf9-5da7-4d38-a692-60d352130202''
    Tue Feb  5 21:57:05 2013 GMT: file ''/tmp/dumps/assert_20130205165703_1.dmp'', upload yes: ''CrashID=bp-8c6890bc-12de-42c2-be3e-d848c2130205''
    Fri Feb  8 01:54:58 2013 GMT: file ''/tmp/dumps/assert_20130207205457_1.dmp'', upload yes: ''CrashID=bp-663f1f44-a563-4138-830c-9a25b2130207''
    Fri Feb  8 01:59:41 2013 GMT: file ''/tmp/dumps/assert_20130207205940_1.dmp'', upload yes: ''CrashID=bp-1df6ec84-452f-4ab9-b62f-2ab742130207''
    Fri Feb  8 02:48:08 2013 GMT: file ''/tmp/dumps/crash_20130207214807_1.dmp'', upload yes: ''CrashID=bp-0364a5ad-d2f8-42cf-b9f0-f905b2130207''

This was on the terminal output shortly before CrashID=bp-0364a5ad-d2f8-42cf-b9f0-f905b2130207 was uploaded:

[0207/214806:ERROR:nss_ocsp.cc(583)] No URLRequestContext for OCSP handler.